Basingstoke Area Group

improvements, design changes, failures, successes and experiments

noreply@blogger.com (Ian Morgan) — Sat, 21 Apr 2012 12:43:00 +0000

It has been some time since my last post. During that time there have been various improvements, design changes, failures, successes and experiments on the electrics underneath the layout. I have still not quite finished, but I do have a working system again.

The original plan was to use Merg Servo4 kits to drive micro servos controlling points and permanent magnet uncouplers. A temporary switch box connected to the 25-way connector on the layout operated the individual points and uncouplers. This was going to be replaced by a different box with Merg CBus kits allowing push buttons to create events which would be used to switch one or more points to set a route. However, I found that the CBus modules would not drive the Servo4 inputs directly, and problems with sharing a single AC power supply burnt out a couple of CANbus circuits.

Meanwhile, developments and new ideas were happening within Merg. I decided to replace the three Servo4 kits with two CANservo2 modules (modified CANACC8 kits). This would mean the connection to a control panel would only need 4 wires (CAN Bus and power supply). A 12V DC power supply bus was also decided upon at this point, rather than the previously recommended 5V power supply.

Another initial design decision was to wire up the layout so that it could be easily switched between analogue DC train control to DCC by swapping a 35 way connector. Either a DCC or conventional controller could be plugged in. However, the new Merg DCC command station kit was small enough and cheap enough to build it into the layout. It also produces a regulated 12V DC supply that can be used by other CBus modules, and uses the CBus connection for attaching the matching Merg hand-held controllers. The capability to switch to analogue control was retained.

At this stage, another problem came to light. The power-on surge caused by the servos was lowering the power supply voltage too much for the control circuits to recover. I decided to add a second power supply bus at 9V DC just to supply the servos, separate from the CBus power supply bus. This has mostly resolved the problem, but there is still a small problem with servos twitching and moving on powering up the layout. This problem is still being investigated.

Still to do is replace the 12V and 9V power supply sockets, as the simple sockets fitted allow the plugs to drop out too easily. I have some latching XLR connectors to replace these. I have also not yet built a control panel. I can use the hand-held controller to create CBus events to select routes, operate individual points or uncouplers, and I can also connect a laptop to the layout, via a USB to CBus interface, and operate the layout using JMRI, so the control panel can wait. I also have to build signals, and fit some more servos to control them.

The first photo shows the underside of the layout with the protective hinged covers closed. The aluminium panel has the DCC command station attached behind it so that the power transistors can be bolted to it to act as a heatsink, if required. At each end of the layout are pairs of CBus 4-way RJ22 sockets for connecting hand-held controllers, PC interface and/or control panel.

The next photo shows one end of the layout with the hinged cover open. The CBus connectors and a CANservo2 module are attached to the lid while the now redundant Servo4 modules are attached under the baseboard along with the servos. The redundant 25-way connector is also visible. Just by the hinge can be seen two servo 'distribution' boards, each with its own 5V power regulator and plugs for up to four servos to connect to.

The other end of the layout shows the second CANservo2 module and the CANcmd DCC command unit attached to the cover, with another pair of CBus connectors. The DCC/Analogue switchover socket can also be seen.

A Case for DCC

noreply@blogger.com (Ian Morgan) — Sat, 20 Aug 2011 10:28:00 +0000

In my last blog entry, I showed my recently completed Merg CAN-CMD CBus controlled DCC Command Station. The Merg kit includes the PCB and all the components to populate the PCB. For future layouts I will probably just mount the PCB directly to a baseboard and hard wire it in. However, this first one I wanted to keep as a portable and flexible unit.This meant fitting it into a case with suitable sockets, switches and Led indicators.

I found a suitable case on Ebay made from black plastic with aluminium end plates and adequate size to take the PCBs and wiring inside.Drilling, cutting and filing all the holes in the aluminium end plates took three evenings to complete. The aluminium plates were then cleaned, sprayed black and lettered with Letraset rub-down lettering, and finished with some clear spray laquer.

Inside the case is the CAN-CMD main circuit board and the CAN-TERM connector kit PCB with two RJ22 sockets. These can be used to plug in a CAN-USB computer interface, or the forthcoming CAN-CAB handheld controller, or to connect to a layout CBus as required.

The one panel has all the CBus related switches and connectors, and the two indicator LEDs. The green LED only lights up if the microcontroller program is running correctly. The Yellow LED lights up when in 'Mini-Booster' mode or flashes when programming locomotives or accessories decoders. The two RJ22 connectors previously mentioned are on this panel, along with two switches. One switches in a bus terminator resistor, required if this unit is at one end of a long Cbus, or used with just a CAN-CAB or CAN-USB. If this unit is connected to a layout CBus that already has terminators fitted then the inbuilt terminator can be switched out. The second switch allows this unit to supply 12V DC to power other CBus items, like the CAN-USB or CAN-CAB. Again, if connected to a layout Cbus that has a separate 12V DC supply, this can be switched out.

The other panel has a socket to connect the power supply, either 12V AC or 15V DC at up to 1 Amp.The screw terminals allow connection to either a programming track or a small layout if using 'Mini-Booster' mode. The mode of this output is controlled by the switch above. The 4-pin mini-Din socket will allow external DCC Boosters (another forthcoming Merg kit) to be attached if more than 1 Amp is required for a layout. The remaining switch controls 12V DC output the the external boosters if required.

A Bus for Freshwater

noreply@blogger.com (Ian Morgan) — Sun, 10 Jul 2011 20:35:00 +0000

Not that sort of of bus - a layout control bus. DCC is really good for controlling trains, but is less suited for controlling points and signals and the like. A separate bus for operating accessories means that a short circuit on the track does not cause points and signals to change at random. The separate bus can also use systems that are more suited to train detection and route selection.

I initially joined Merg (Model Electronic Railway Group) in order to access their servo controller kits, for controlling points and signals. Having joined, I found out about their development of a layout control system based on the CBUS two-wire command bus. The CBUS protocol has been used in all new cars for a number of years, to reduce the complexity of the wiring loom, and increase the functionality. It is a fairly simple protocol, compared with TCP/IP as used by the Internet. The bus is used to join up various devices all over the car. It allows 'producer' devices (switches, or sensors for instance) to broadcast simple numbered 'event' messages over the bus. All the 'consumer' devices attached to the bus will see these 'event' messages, but certain devices will be setup to perform specific functions when specific events are seen. Thus a switch can broadcast an event which the windscreen wiper controller will act on to start the windscreen wiper motor. A rain sensor can be set up to broadcast the same event. It might also broadcast another event which would result in the headlight controller lighting the headlights. The CBUS is equally useful for controlling a layout. Control panel switches and train detectors can become 'producer' devices, and point motors, signal motors and mimic display panels can become 'consumers'. Because of the widespread use of CBUS in the automotive industry, the basic components required are readily available and low cost.

Last year, I purchased a couple of Merg kits, an eight input 'producer', and an eight output 'consumer'. I also picked up the experimenters kit, a small board with eight switches on that plugs onto the 'producer' kit, and a board with eight LEDs on that plugs into the 'consumer' kit. The Merg kits are designed to allow them to be 'programmed' using small switches that are part of the kits. The 'producer' can be told what events to broadcast for each switch operation, and the 'consumer' kit can be taught which events to listen for, and which LEDs to light or extinguish when the event is seen. The Merg kits were designed to use a 5VDC supply distributed from a power supply regulator on one of the kits, which required a 12-16V supply. I experimented with these modules, but did not get round to using them on Freshwater as deadlines approached, and a temporary 'traditional' control panel was built. I do intend to use CBUS eventually as it will allow simple route selection and some interlocking to be implemented.

The photo shows a 'producer' board on the left, with eight yellow switches on the experimenter board plugged on the end. On the right is a 'consumer' board, with eight red LEDs on the experimenter board plugged on its end. They are connected by the 2-wire bus (blue and white wires). The orange and black wires are the power supply lines. In the centre is a C-BUS connector board, and a power supply can plug into the lead coming down from the centre. I have modified these boards to run from a 12VDC supply instead of the 5VDC supply that the kits were originally designed for.

Over the last 12 months, more kits have become available, along with interfaces to a computer to simplify the programming of the modules. The computer interface also allows computer control of a layout, using suitable software like the freely available JMRI. The latest development from Merg is a DCC command unit and a hand-held controller. The CBUS is used for communication between the controller and the command unit. JMRI can also be used as a throttle connecting to the command unit via the CBUS.

So, to prepare for the DCC system, and use of the CBUS on Freshwater, I purchased the Merg kit for a CBUS to USB interface. This was initially built as per the instructions. It is designed to take a 5VDC supply. I therefore created a simple 5VDC regulator circuit on a small piece of veroboard, and mounted everything in a small black plastic case. A 4 way cable with an RJ22 type connector at the end that can plug into a Merg CBUS connector kit, comes from the box, connecting the two bus wires and the 12VDC supply into the box. A standard USB connector protrudes from the other end of the case.

Having a working USB interface, I set to building the DCC command station kit from Merg. This has been built as per its instructions. It is already designed to take an external 16VAC power supply, and can supply 12VDC to other devices on the bus.

The photo shows the USB interface box on the left, which connects to the USB port on a PC. It also plugs into the CBUS connector board and the bus then connects to the DCC command station board on the right, the red and black wires next to the bus wires have a socket for connecting the power supply. The red and black wires to the far right attach to the test track at the top of the photo. The white round object at the bottom right is a buzzer used as a short circuit warning. This setup now works, using a JMRI software throttle on the PC. I have also played with a Wi-throttle 'app' on an iPhone using a WiFi connection to the JMRI server on the PC.

Merg will very soon have a kit available for a hand held DCC controller that will plug directly into the CBUS connector board, and do away with the need for the USB interface and PC. Watch this space.

Bridging the Gap

noreply@blogger.com (Ian Morgan) — Sun, 06 Mar 2011 19:17:00 +0000

Now I have taken on a new deadline for Freshwater, the 2mm Expo at Keighley, I am now motivated to get on with the scenics. First off, a bit of terra-forming. As I had some sheets of foam-board available, I thought I would use some to build up the contours. Most of the station area is flat, so it is only the river banks and the start of a small hillock behind the station that needed building up. When I have smoothed out the slopes, I intend to cover it with PVA soaked kitchen towel. I hope to avoid having to use much filler, as the board does twist and move a bit, and filler will probably crack and break up.

Only a small number of buildings are needed for the layout, so I want to avoid using kits (except for the ratio concrete platelayer's hut probably), and scratch build as much as I can. Starting with the basic civil engineering, I need a bridge over the tidal River Yar. I have not found any photos of the real bridge, so I need to freelance it. I would have liked to build a dainty little bridge with hand rails, but rail cleaning at exhibitions would probably destroy them. Therefore, I decided on a large girder type bridge, giving plenty of clearance for the tide to come in.

The main girder and end pillars were cut from a single piece of plasticard, then further layers of plasticard were added to build up the pier thickness. By using a single piece, the piers and girder will always be at right-angles to each other, and will not move when the bridge is fitted in place. Strips of thin plasticard have been added to complete the girder. In the photo, only the nearest girder is complete.

When the girders are complete and painted, they will be glued in place, and the abutments below the bridge will be completed in place. Brick paper will then be applied to finish off the abutments and piers. Hopefully, all will be complete next week. Then I can start on the platform. The original platform was brick edged, then it was extended using concrete panels, and then another extension was added with concrete pillars. Should be fun.

Ballast (A Disaster)

noreply@blogger.com (Ian Morgan) — Thu, 28 Oct 2010 12:09:00 +0000

It must be the season for ballast laying. With all the track laid, wired up and painted, and a successful two days operation at the GJ Expo in Oxford we just needed an opportunity to have the layout set up for a few days to allow the ballast to be laid and for the glue to dry.

We followed the method used on previous layouts, applying the ballast dry, painstakingly moving around and removing it from sleepers and flangeways, then spraying water with a couple of drops of washing up liquid through an atomiser to make everything wet, then dripping watered down glue on it. There must be a less tedious way of doing it, but this works.

Previously I have used fine granite dust from the Mendips and PVA glue. This sets like concrete. This time I used Woodland Scenics finest grey ballast and Copydex. This combination should produce a more flexible result, better suited to my thin baseboard surface, and may reduce running noise (although I am not too bothered about that). I found the Tamiya disposable paint brushes very good for final removal of individual stray peices of ballast from the sleepers.

The photos show the job in progress. In the photo below you can see the white watered down glue just after application. It dries clear and matt. I expect it will take a few weeks to clean up the track and remove all obstructions from the flangeways, and a lot of glue disappeared down the holes into the point mechanisms below which will need some sorting out. It may be some time before proper operation is resumed.

(Footnote)
Well, 24 hours later, it all looked good, but as I tried to remove a stray piece of ballast from the inside of a rail, it pulled a long string of elastic glue with pieces of ballast in from between the sleepers. A light brushing with a toothbrush lifted lots of nasty elastic clumps of ballast. There was no way it would survive exhibition use. So, the bad areas were patched with fresh ballast, and the whole layout doused in watered down PVA. I am hoping the PVA will solidify everything rather than just form a crust on the surface, but I will find out tonight. If it fails, all the ballast will have to be removed, and we will have to start again. Oh dear :-(

Ian.

Another Servo problem solved

noreply@blogger.com (Ian Morgan) — Sat, 14 Aug 2010 14:07:00 +0000

Not much progress on Freshwater for a few weeks because another problem arose with the servos used for points and uncoupling magnets. As I was adding more and more servos to the layout, I started getting problems switching on the power. On switch-on, the servos would move rapidly, hitting the physical limits of the mechanisms they are attached to, and carry on trying to drive past them. The current drawn by all the servos was collapsing the voltage from 16V AC down to about 3 volts. All this was happening before the PIC microcontrollers had time to initialise and bring the servos under control, and the voltage then dropped below the PIC operating voltage, so they stopped doing anything.

Consulting the Merg forums, I was advised to add some pull-up resistors to the servo signal lines. Apparently this stops the switch-on spike which sends the servos trying to reach their end limits long enough for the PIC microcontrollers to initialise and start sending sensible control signals to the servos. The pull-up resistors are 10k ohm, large enough not to affect normal operation. A change to the PIC software to speed up the initialisation process was also suggested, but has not been necessary. Having added the resistors, everything seems to be operating correctly again.

So, now I just have to build one more servo operated uncoupling magnet set and the electrics under the layout are done. Then I can start ballasting the track. Other jobs in the queue are:

- building a lighting gantry
- adding backscenes, and a transportation case
- replacing the temporary control switch box with a proper control panel (using CBUS kits to allow route setting)
- building a larger fiddle yard now the GJ challenge constraints are out of the way
- creating buildings and scenery

Ian Morgan
Hampshire

Magnetic uncouplers for Freshwater

noreply@blogger.com (Ian Morgan) — Sun, 18 Jul 2010 16:54:00 +0000

Following the Expo, I can now get on with adding the uncoupling magnets. I had always intended using permanent magnets, following their successful use on Brunswick. I bought some small magnets from Merg, but they were nowhere near powerful enough to operate the DG couplers. Now I have purchased 50 'rare earth' magnets via Ebay. These are really powerful for their size (about 5mm diameter and 3mm long) and come with all sorts of warnings. 'Rare earth' magnets have a high iron content and would corrode very quickly if not protected by a special coating. Often this is nickel plating. It is therefore not practical to cut them, and you have to protect the plating from damage.

I planned to use some more servos, as used to operate the points, to move the magnets into position under the track, or away from the tracks when uncoupling was not required. The layout has several parallel tracks at various positions where I wanted uncoupling to take place, so I planned to have a number of magnets alligned to the parallel tracks, all operated by a single servo. I cut a length of paxolin sheet, and drilled it to take the magnets, which are glued in with epoxy. Working with the magnets is interesting, as they fly around the workbench attaching themselves to tools each time you get anywhere near them. Trying to get three magnets into their holes in the paxolin to glue them without them flying to each other was also quite fun.

I made a paxolin 'arm' which bolts to one of the servo attachments, and the bar with the magnets attaches to the arm, using bolts and a paxolin block with threaded holes in it. Because of al the tracks above where the servo needed to be, I cut a sheet of hardboard to attach the servo to, which bolted under the layout away from the tracks. The photos show how it works, I hope. One shows the magnets moved well away from the tracks, and the other two show the magnets in position hard against the underside of the layout surface, below the three parallel tracks there. You can also see the Merg Servo4 board that the servo plugs into. Now I just need to build two more.

Freshwater Behaved Itself

noreply@blogger.com (Ian Morgan) — Mon, 05 Jul 2010 20:32:00 +0000

We had a great weekend at the Expo - lots to see and spend money on. Dave Stratton lent a hand carrying and operating, allowing me to roam a bit with the video camera.

I had the layout operating with nearly a week to go, and I chose to give the track a last minute paint job. I did not find time to add rust to the rails, just a spray of undercoat, and some paint slapped on the concrete and timber sleepers. It took an hour to scrape the rail tops and free up the point blades, but it was ready to go when the doors opened.

The layout performed a treat all the weekend, once the rails and wheels were cleaned and the back-to-back of several wagon wheels reset using the gauge. I am really glad I concentrated on getting the track right rather than pressing on with the scenery, as it is a pain to sort out with delicate buildings in the way. Now I can start laying ballast. I was definitely not going to do that before the Expo.

Uncoupling was achieved using a hand held rare-earth magnet waved about underneath the baseboards. 50 small rare earth magnets have now arrived in the post (ebay) which I will now produce a mechenism for. To shunt the kick-back siding, couplings had to be added to the other end of locomotives which previously only needed one coupling for shunting on Coley Park. It does add some interest to what is a much smaller goods yard though.

The servos and merg Servo4 control boards worked perfectly and did not require any attention all weekend - very promising.

The ability to switch from analogue DC to DCC and back again was of interest to some people, and when a wheelchair-bound friend turned up, we managed to lower the complete layout for him, using the adjustable trestles, returning it to our height later. This was not as easy as hoped, and will probably not be repeated, but it does show that we can chose what height to set up at before each exhibition.

I just have this out-of-focus pic of Dave shunting:

Ian Morgan

Fresh(er)water wiring completed

noreply@blogger.com (Ian Morgan) — Sat, 26 Jun 2010 20:15:00 +0000

A weekend exhibiting Coley Park at Yeovilton followed by a weekend in Slovenia on a business trip slowed progress, but last week saw the completion of the wiring for the point operating servos to a 'temporary' switch box which will be replaced by Merg CBUS control one day. Unfortunately, two of the Merg Servo4 controller circuits I built last summer failed to respond to the setting up box. I only had 5 of the 7 points working.

However, I checked the Merg forums and it seems that there was a fault with programming the PIC microcontrollers for the kits last year (since fixed). An email to the Merg kitmaster saw a speedy response, and two new microcontrollers turned up in the post this morning. They are now fitted and working, and the two faulty ones will be returned for re-programming. Many thanks to Martin (Merg kitmaster).

The fiddle yard has one length of track laid and wired up, but that is all for now.

I have also added some more bits of wood to the underside of the baseboards to protect the wiring, servos and circuit boards during transit, and have purchased wood and bits to build the lighting gantry, but it was just too hot to do much today.

So, at the AGM, there will be plain, unballasted track and no scenery, but quite a lot going on underneath the baseboards, and hopefully trains running (analogue DC and/or DCC).

Ian Morgan.

Another milestone - trains running

noreply@blogger.com (Ian Morgan) — Sun, 06 Jun 2010 10:48:00 +0000

This week saw the completion of the track wiring, and the successful test running of trains all over the layout. There was just one missing link wire found. Wiring up the point operating servos is still to be done. From the photos you can see one Merg Servo4 board mounted under the baseboard. Two more of these will be fitted to control the remainder of the points, and the, as yet, non-existant uncoupler magnet devices.

One inovation I have added is to allow instant switchover from analogue DC operation to DCC operation. The rails are divided up into sections, as normal. Individual lengths of rail in a section are linked up by the copper tape runs beneath the layout. The point 'frog' sections are kept as short as posible, and are fed from microswitches operated by the point mechanisms, switching between the two adjacent stock rails. Each rail 'section' is kept separate on the layout, and are fed by wires from a single multipole connector (an old Centronics parallel printer socket with 36 pins.

I then added wire links inside a plug to connect the sections together. For analogue DC, siding sections are linked to 'frog' sections so that they are isolated by the points. Another plug, for DCC operation, would link together all the left-hand rails, and all the right-hand rails, and leave the 'frog' sections unconnected.

SR Buffer Stops

noreply@blogger.com (Ian Morgan) — Sun, 11 Apr 2010 19:54:00 +0000

At last, some spare time for modelling this weekend, so I worked on making up the lovely etched buffer stop kits I got from the 2mm Scale Association. I had started one a few weeks ago, but a good day's work today sees completion of all five required by the layout.

These kits make a form of buffer stop I was not familiar with, but I have found a very similar looking one at the eastern end of Ascot station, unfortunately not in easy reach of a camera though.

The beautiful, and cleverly designed etch is in nickel-silver. I really like using this material. The etch folds up, eventually giving 6 layers which all line up accurately for 'sweating' together with the soldering iron. The triangular gussets that attach the front 'leg' to the rail are a bit fiddley to line up and attach though.

I used real wood (recycling a coffee stirrer) for the beams rather than using the 5-layer etched beams provided. It feels more appropriate, and is electrically insulating, but proved tricky to attach using superglue. The tie-bar passing through small drilled holes in the uprights was a bristle from a large brush - also electrically insulating.

It seems my painting skills have lapsed over the long period since I last did any, and my hands seem to be not as steady as they used to be, but applying red and white paint on the ends of cocktail sticks, I managed to straighten up the lines fairly well.

Fresherwater tracklaying completed

noreply@blogger.com (Ian Morgan) — Mon, 01 Mar 2010 10:28:00 +0000

A milestone (or is that a millstone?) has been reached. All the track is now laid, except for the buffer stops which will be the eagerly awaited etched SR kits. I have made a start on installing the dropper wires, and one point mechanism and servo is in place, so I have some way to go before proper testing of the track can start.

As can be seen from the non-painted track, there was a lot of curved track required (half track created in the jig, then the second rail being added using triangular gauges once glued in place). I had some shorting sleepers on these stretches which had to be sorted out in-situ and took some time to find and fix. This is one advantage Easitrac has over copper-clad.

I would like to get the wiring done by the end of March, but we have the Basingstoke exhibition using up one weekend (Highbury colliery will be there).

Yet Another Point Tie-Bar Mechanism - 2

noreply@blogger.com (Ian Morgan) — Sat, 30 Jan 2010 23:15:00 +0000

Here is how the mechanism described in my previous post is fitted below the baseboard and the point. Remember, the point blades are fitted with operating wires, formed using the Easitrack bending jig, so the point has two vertical operating wires dropping down near the ends of the point blades. Two small slots are drilled and carved in the baseboard surface before gluing the point down. The slots are wide enough to allow the brass tubes from the operating mechanism to pass up through them, with enough sideways throw to allow operation of the point. This photo shows the point in position. When it is ballasted, there should be very little of the mechanism visible, I hope:

The mechanism is glued underneath the point. As it is put into position, the two operating wires dropping down from the point must be threaded into the two tubes of the mechanism. The ends of the tubes will be just below the top surface of the baseboard when located properly. Some rigid brass wire with an omega loop formed in it is hooked into the hole drilled at the end of the PCB in the mechanism. I am using servo mechanisms to operate the points. These are very cheap on Ebay. I have some MERG Servo4 electronic kits to drive them (each board will drive up to 4 servos) and the first of the MERG CBUS kits will be used to control them. More on the electronics will be in a later blog posting. I had hoped to glue the wooden blocks that the servo is mounted on to the baseboards, but the glued joint was not strong enough, so small countersunk screws have had to be added which will have to be covered by the scenery.

Yet Another Point Tie-Bar Mechanism

noreply@blogger.com (Ian Morgan) — Tue, 26 Jan 2010 17:38:00 +0000

I purchased an Easitrack point operator and put it together, and I was impressed by the engineering, and how nicely it operated. The problem with it was, though, that my baseboard (being a hollow door) has a very thin surface and only an inch or so overall depth. I could not see how I could fix the mechanism in place, and much of the operating mechanism would be hanging below the baseboard, where it would be easily damaged in transit.

Up to now, I have used moving tiebars (copper clad glass fibre board) operated by relays from below. Although I had found them to be simple to produce, and reasonably reliable, they are a bit disappointing to look at. For Fresherwater, I wanted to try something better. The Easitrack blade wire bending jig provides an answer to my main worry over many solutions in that the wire bends and passes below the stock rails, so the blade tips cannot rise up and get caught while track cleaning. I am still worried that if the solder joint between the wire and the point blade fails, I will not be able to repair it with the track laid, but we will see if that worry is justified.

In designing a new mechanism, I had to take my notable lack of engineering skills into consideration. The mechanism had to operate with large tolerances in almost all measurements. Where I work, tea and coffee comes in pouches which hang from plastic channel 'rails'. Consequently, large numbers of these pieces of plastic end up in the bin each day, so I took it on myself to try to recycle at least some of them.

I started by cutting a length (about 2 inches) and removed some of the side pieces at the ends. It is soft flexible plastic, easily cut with a scalpal. Then I cut two rectangular slots that small brass tubes will pass through, and move lengthwise to operate the point blades. In the photo below, the channel as it comes is on the right, and the cut up piece is on the left:

I then took the L- profile pieces I had cut from the sides and glued them with epoxy resin so that they restricted the size of the channel. These are just visible in the photo. I also glued a small micro-switch in place on a piece of paxolin board:

Next I cut a strip of single sided glass fibre PCB, wide enough to pass smoothly along the inside of the channel. I cut this strip into lengths of about an inch and a half, and made some insulating gaps. I drilled the end for an operating wire, and around the centre for one of the small brass tubes. I left drilling the hole for the second tube, as that is the only critical measurement, and will depend on the point it will be attached to (the way I make them):

To the opposite end from the operating wire hole, I soldered a bent piece of rail with a 12BA nut on the end. The bolt through this nut will operate the microswitch, allowing some final adjustment once in place:

Now I needed a jig to help solder the small brass tubes in place, and here it is - a few pieces of old plywood, and a stiff wire pushed into a drilled hole. The tube sits over the wire and stands vertically while the PCB sits on the top of the ply ends, leaving the right amount of tube protruding below:

So there we are. Having created the first one, I easily made 6 more almost matching ones for the rest of the layout in one evening. How they fit, and work will be revealed in the next installment.

Ian M.

First piece of track laid

noreply@blogger.com (Ian Morgan) — Sun, 25 Oct 2009 11:40:00 +0000

There has been a bit of a pause in progress while constructing the track required. As I only have one evening a week to allocate to modelling at the moment, it has taken longer than I would have liked. I also found a new way of slowing up progress by deciding to try filling the insulation cuts in the copper-clad sleepers with milliput (after checking the gaps were actually insulated). With a spray of primer (after washing with Cif and a finger nail brush) they really do look better for being filled.

I also built some MERG servo control boards and a tester/programmer box, as I will be using servos to operate the points and uncoupling magnets. More on these subjects will come later, I hope.

Anyway, the first length of track to be laid is across the board join to the fiddle yard. I am trying out the easytrack brass sleepers for this. Six of these sleepers were soldered in with concrete sleeper profiled copperclad, and the whole lot primed. I had to smooth out my poor carpentry by planing the surface slightly, and digging out a little to cater for the brass sleepers being fractionally thicker than the copperclad ones. The whole length was fixed down with Araldite and weighted down overnight. This morning I have sawn the rails across the gap, and sawn the brass speepers in half to restore insulation between the rails. A little more Milliput filling is required before painting the sleepers, and ballasting.

The photo also shows some foamboard being used as a basis for the river banks. The river is still tidal here, so it will have steep, deep banks.

The first point will be situated just beyond the bridge, so I now have to decide on, and build the operating mechanism, more on that next time.

Changing my Mind

noreply@blogger.com (Ian Morgan) — Fri, 01 May 2009 22:34:00 +0000

Not a lot of visible progress for a while, but I have been beavering away building track. Having built a couple of points using the jig I have (equivalent to about 3 foot radius) I scanned them, and printed paper copies which were cut out and used for trying to mark out the track layout on the baseboard. Try as I might, I just could not get the track to match the original layout, with the outside slip. So, I decided to revise my plans, and follow the later track layout without the slip. This also means losing the locomotive facilities, but does reduce he number of points that need to be built. The revised layout plan is shown below:

I also used the scanned images to put together a template for the crossover at the buffers end of the platform road. With some care and attention, I managed to build most of it in the point jig, re-inserting the construction into the jig in different orientations a few times.

If I had realised that the jig is exactly the right width, I could have used it as a sawing jig for the full length sleepers. Note, I have not used chairplates for this layout in a bid to save time. Previously, when I have used chairplates, the daylight gap beneath the rail disapeared during ballasting anyway.

Here is the track built so far. Three more points and plenty of plain track needed for the layout board. More needed for the fiddle yard.

Having tried traversers, sector plates, turntable points and cassettes on previous layouts, proper points have proved to be the most reliable solution, albeit they take up a long length of the fiddle yard. I will be attempting a 4-way point for this fiddle yard. Wish me luck.

More Fresherwater Progress

noreply@blogger.com (Ian Morgan) — Sat, 21 Mar 2009 23:23:00 +0000

After some consideration, I decided to change my mind about moving the road. Instead, I added a couple of pieces of wood below the baseboard ends to reinforce the cutouts for the river bed, and added the second cutout on the front edge. I also added four small squares of wood to make locating the trestles better defined. Both these additions can be seen in the following photo:

The photo also shows a brick holding down the river bed while the glue dries. Three layers of 5mm foam board were used to form the river bed, and the stream bed that runs along behind the platform. The ends of the river that pass over the board edges had the foam and the lower face removed, and will be glued to the woodwork separately (hopefully leaving the river surface smooth). The banks will be formed from more foam board later.

Baseboard progress

noreply@blogger.com (Ian Morgan) — Sat, 07 Mar 2009 15:44:00 +0000

Another Saturday morning, and some more progress. The trestles I purchased cheap on the Internet turned up, and I have assembled them. They are just what I had hoped for, and make a steady, sturdy support for the layout, and adjust from really low (for a layout) to a bit too high.

The cabinet makers dowels and catches also turned up in the post, and so the fiddle yard board now connects to the layout. My poor carpentry skills let me down a bit, and I have ended up with a little step to be dealt with when track laying, but it should end up OK.

I scratched my head a bit over supporting the far end of the fiddle yard. The catches and dowels would not survive the stresses for very long, but the weight to be supported at the end of the fiddle yard is not very heavy. I did not want to resort to a leg, as it would not be adjustable in height like the rest of the layout. There was not really anywhere to mount a diagonal brace to, easily. I had an idea about cantilevering somehow. I found a suitable piece of timber about 5 feet long, and attached small pieces of timber at each end (see photo above). The centre of the timber rests on top of the trestle, and the attached pieces of wood hook under the layout and fiddle yard at each end (see photo below). It seems to work, but I might add some catches to hold it in place.

So, that is it for this week. The layout needs a backscene board, and I will put a safety fence around the fiddle yard. I also want to build boxes to protect the layout for transport and storage. All this heavy woodworking needs to be complete before track laying starts. I had better start building some track to lay.

More hacking at the baseboard

noreply@blogger.com (Ian Morgan) — Sat, 28 Feb 2009 12:57:00 +0000

After last weekend's work on resizing the door, and making a cut-out area underneath the layout for the point mechanisms, etc, to go, this weekend's activity was a little less to do. The glue having set, all the edges were sanded down. Two cross members were screwed and glued across the underside. These will be used to locate the board on the leg trestles, but were also intended to strengthen the layout before the cut-outs for the stream and river Yar were made in the layout's top surface:

The rounded ends of the new cross members can be seen below the layout, about 4 inches in from each end. They also mean that the layout does not lie flat on the floor when off its legs, and can be picked up more easily.

The 6 inch grid has been drawn on the topside of the layout, and the trackplan sketched out on it. The locations of the strengthening timbers around the underside cutout have also be marked, to help me avoid them. The areas for the stream and river were then cut out with the jig saw and the cardboard lattice removed. The level of the river bed will not be the full depth of the door thickness. It will be as deep as the cutout in the edge timber.

I shied away from making a similar cutout in the timber at what will be the front of the layout. I decided, instead, to move the road bridge downstream a little so it covers the timber. I may change my mind again later, once I have completed the fiddle yard connection. Now, I can just await delivery of the leg trestles, and brass baseboard joining dowels. I intend to complete all the woodwork construction, including backscenes and transportation/storage boxes before starting any track laying.

Time to throw my hat into the ring

noreply@blogger.com (Ian Morgan) — Tue, 24 Feb 2009 21:05:00 +0000

Since the 2mm Scale Association laid down their Golden Jubilee Layout Challenge to build a layout of 9.42 sq. ft. or less in time for their 2010 Expo, I have spent a year and a half thinking about it, and now I have a year and a bit to actually build something.

The thinking bit was quite tough, coming up with criteria to be met by the eventual design, and then getting a design that met most of those criteria. The criteria included:

- max area 9.42 sq ft, of course
- maximum baseboard length, 5 ft (for transport)
- interesting to operate and view
- not too complex, given the time constraints
- Southern region, BR 1950's - 1970's
- based on a real location

Finally a suitable prototype presented itself, although it does require generous use of modeller's license. The location is the terminus at Freshwater on the Isle of Wight. Combining a scan of a large scale O.S. map onto the satellite photography of Google Earth, I found that it easily fitted on a 5 ft. by 1 ft 6 inch baseboard, with a fiddle yard of 2 ft 6 inches by 9 inches (total area 9.375 sq. ft).

The original track plan shows lots of interest, with the kick-back sidings and outside single slip. Unfortunately, the layout was rationalised between the wars, and the slip, and two sidings serving the loco facilities were removed, along with the short siding to an end loading bay. An extra spur from the run round, making 3 bufferstops by the station building was added though. For operating interest, all the track from both periods will be retained:

(the purple lattice is 6 inch squares)

To make it possible to extend the operating life of the line, and allow more variety of stock to be used, I have invented a new course of history. Following the war, it was decided to keep the Isle of Wight's rustic charm by banning all road improvements on the island, and restricting motor vehicle use to residents and local businesses. Money saved was put towards the Lymington-Yarmouth rail bridge/tunnel link. All the existing rail routes on the island were then relied upon to convey produce, supplies and holidaymakers. (Britain's version of NASA was based near Freshwater, and might have generated some traffic if it had not been abandoned).

The line from Yarmouth to Freshwater thus became a short branch, with direct trains from Newport and Cowes. Excursions from the mainland would need to reverse at Yarmouth. This new history and generous use of modeller's license means I wil call the layout "Fresherwater".

So much for the ideas, time for something practical. On a visit to the closing down sale at our local Trade Depot I found a pile of plain plywood doors for just £4 each. I felt sure I could do something with one of them, and for that price, I could just dismantle it and use the plywood. First, I would try to make use of the strength of the door's construction.

I started by cutting the door down to 5 ft. long. That is when I realised the faces were not ply, but MDF made to look like ply. However, I continued with my plan, and fitted a length of timber into the cut end, glued and clamped. Then the door was cut lengthways to bring it down to 1 ft. 6 inches wide, and another length of timber glued into the gap at the edge, to give the door its strength back again. The offcut from the end of the door was trimmed to 9 inches, and a length of timber glued in to form the fiddle yard.

Next, I drew out the layout (mirror imaged) to what will be the underside, to determine where point motors and uncoupler magnets will go. This area was then cut out, and the cardboard lattice strengtheners removed from inside the door. More timber framing is then glued in along the edges to return the strength. The photo shows the edge timber clamped while the glue sets, and the first of the timber framing around the central hole in place. So far, the baseboard is still light, and nice and rigid. Note this will be the underside of the layout:

08 kit building - Part 7

noreply@blogger.com (Ian Morgan) — Sun, 15 Jun 2008 23:13:00 +0000

It is over a year since my last posting. I had been making excuses, such as pressure of work commitments, life, looking for a good way of blackening the chassis, etc, but mostly it was down to being disappointed in how the chassis was running. Anyway, Friday 6th June, I got all the bits out of the box again. The rusting tube the worm is mounted on was cleaned up with emery and oiled, and found to be running smoothly in the chassis with just the worm gear on its idler shaft.

Adding the next idler gear messed things up though. It looks like the worm gear is slightly non-concentric on its shaft. The bearings have been opened up to give a little play, but adding the next gear took away thay play. So, some more careful opening up of the bearings eventually resulted in free running of the gears.

By now, the stub axles used by the idler shaft muffs were quite a loose fit, and kept dropping out. It was time to glue them in place. For the second shaft, with the hole drilled in it, this was a simple matter of applying some super glue into the hole on the end of a pin. The worm gear shaft is trickier, because there is no room for such a hole. I inserted a small piece of plastic rod to ensure the two stub axles can never meet in the middle. Then I tried adding some glue into the muff, putting it into position, then inserting the stub axles through the bearings. First I tried superglue, then I tried Uhu. No real success with either, except that I managed not to glue the muff to the chassis. However, the stub axles are now a tighter fit, and might stay put.

The rear wheels were fitted next. The muff had to be reamed out quite a lot, but still retaining a tight grip on the half axles. Everything was still nice and smooth. Adding the centre wheels locked the whole chassis up though. The gear was hitting the solder and folded tab of the spacer fitted above it. The solder, and some of the tab was carefully filed/chiselled away until there was clearance. The same was done for the front wheels, but eventually, on Friday 13th, all wheels were turning sweetly, and very slowly, under motor power.

The chassis had been blackened using a CD marker pen. It needs touching up after all the fettling, but it is a quick, easy way to do it.

08 kit building - Part 6

noreply@blogger.com (Ian Morgan) — Tue, 05 Jun 2007 10:42:00 +0000

Having completed construction of the N Brass rolling road (plus the extension kit ready for the 9F) I turned my attention back to the 08 last Friday evening. Dave Stratton had attended a chassis construction group and has his gears and wheels all installed now, so I was lagging behind.

I was unhappy with the worm gearbox on mine, and with just the motor and worm fitted (no gears) it was very rough compared to when the motor was out of the gearbox. Flexing the gearbox did allow the motor to speed up, but I just could not make it stay like that. Eventually I realised the gearbox had folded up not square. I removed the bearing from the far end and the worm rod was naturally hard against the side of the mounting hole rather than in the middle. I took the gearbox apart at the fold lines, filed the edges square and soldered it back together square, so that the worm rod was central to the bearing mounting hole, and when the bearing was added, the motor still ran smoothly and very, very slowly.

Now I think I stand a chance of making it work with some gears in position too. However, I want to blacken the chassis first.

08 kit building - Part 5

noreply@blogger.com (Ian Morgan) — Sun, 25 Feb 2007 12:55:00 +0000

This Friday we had balsa wood (courtesy of Dave Stratton) so I could add the wires cut during the last session to the brakes. At this point we noticed that there are another set of brakes on the thinner etch. I presume these would have been easier to fold and drill than the ones on the thick etch, but maybe not so strong in use, so we will use the thicker ones.

Threading in the wires, and soldering up, as per the instructions,was straight forward enough, and the photo shows them with most of the wires trimmed and cleaned up. I will cut the remainder later, as I expect the length will be critical to hold them in place with the outer frames, without fouling the gear chain on the one side.

The next stage will be to paint or blacken the frames and wheels ready for final assembly before progressing with adding the cranks and connecting rods. There will be a few weeks gap before the next session, as we have our own Basingstoke Exhibition coming (March 10th/11th - very good value) and then we are helping Jim again at Nottingham.

08 kit building - Part 4

noreply@blogger.com (Ian Morgan) — Sat, 03 Feb 2007 17:55:00 +0000

Last night's session started by me having to free up the rusting worm tube and extract it from the bearing. I cleaned it up again with emery paper, and got everything running freely again, but left it dismantled this time. I must put some oil on it to stop it rusting again.

Having dismantled everything, this evening was a less-than-exciting session of drilling .35mm holes (the smallest surviving drill I could find in my toolbox). Twelve holes in the chassis, and another 18 in the folded up brakes. However, Dave Stratton and I managed to complete all this without breaking a drill, which makes a nice change for me. I then cut 18 half inch lengths of .3mm nickel-silver rod ready for soldering,but as we did not have any balsa wood, that will wait for the next session.

08 kit building - Part 3

noreply@blogger.com (Ian Morgan) — Sat, 20 Jan 2007 21:55:00 +0000

We were very pleased to be joined by Paul Martin for last night's session, but as he accepted some of our tea, he may well be back in hospital pretty quick. He had his 08 kit with him, and although he read the instructions and looked at the bits, we did not manage to persuade him to start construction - yet.

Dave Stratten and I started by cutting up bits of the axle steel into bits approximately 3.5mm long, using a vice and slitting disk. The gear muffs were drilled and reamed until the axle steel would push into them (1.6mm drill was used eventually).

I fitted the lay shaft with the gear at each end first, using a 1.5mm drill first, then pushing it through with one of the short lengths of axle steel. This method worked quite well. The larger gear was catching on the stretcher tab, so it was filed back a little to clear the gear.

Next would be the worm gear lay shaft. The muff for this one needed shortening as the bearings are further in. Another problem is the fitting of the gearbox over one of the bearings. Excess solder was filed away to allow it to fit, but it was apparent that one of the gears on the already fitted lay shaft needed to be away from the end of the muff to clear the gearbox. The smaller gear had been glued to the end of the muff last week, but the larger gear could be pushed right up to the collar to give clearance. It does mean that the gear train to the wheels is on the opposite side to the model in the instructions, but hopefully that will not cause more problems. To turn that lay shaft round, I had to file the other stretcher tab to clear the larger gear.

You can see the gearbox tab and how it fits next to the gears in the bottom left of the second photo.

Note that the tube that has the worm on it is rusting rapidly, although I am sure I did not get any flux near it.

With the two lay shafts and the gearbox in place, power was applied, and it whirred away smoothly, but slowly. Very satisfying, but I think it needs loosening up a bit. Not sure yet if the gearbox has to be fixed in place, or left to float.