Introduction to Somerton Model Railway

The base concept of Somerton Model Railway is to create a large layout which can run a number of trains simultaneously under automatic control. The layout is housed in a converted double garage which measures approximately five metres by five metres.

The scale is 1:76 and the track gauge is 16.5mm, a standard more commonly known as ’00’, a quirky combination used by British modellers. All of the track used is code 75 made by Peco and all of the points and slips have live frogs. The points or turnouts are driven by Tortoise slow motion motors with built in switches which are used to energise the frogs and to provide positional feedback. The control system is dcc and is made up of Digitrax components along with some hand built Arduino based boards. Computer control is achieved by using Train Controller software from RailRoad & Co, decoder programming uses JMRI and the Arduino boards are programmed by hand.

The layout is built on two levels, the lower of which contains a large storage yard which is normally hidden from view. There are two helices at either end which both carry double tracks to the upper level which is a scenic area. At the time of writing, plans for the scenic area are still vague but the intention is to have a mainline station, a traction and maintenance depot and possibly a freight / industrial area. Urban, rural and canalside scenery will hopefully be modelled. Other than modelling a mainline station, there isn’t any intention to model a particular area and the era is nominally any time from 1950 to the present day. Signals will all be coloured light rather than semaphore and there will be some degree of overhead line electrification.


Test Track

Track laying

So what’s happened in the last week? Well, I’ve been laying the track that makes up the second set of storage sidings on the Southern and Eastern sides of the room. It’s a long and often tedious job, starting with the turnouts which need to be wired up before they are pinned down. Then the point motors need to be wired and installed. Each motor has eight soldered connections and the turnouts have three, so for this part of the project that’s 121 solder points, 121 wires to be routed back to the connection blocks, 121 wires to be cut and stripped and 121 screw connections to be made. As I write this today, I have laid around 40% of the storage tracks, hopefully one more day should see that work completed and then I can start work on the second helix.

Baseboards Planning Track

Back to the drawing board

I’ve been using Anyrail software to plan the track layout so after finalising the pointwork design for the second storage yard, I printed the plan off at full scale.

The Anyrail track plan being assembled sheet by sheet.
Storage sidings in the southeastern corner
Creating the board extension under the track plan.

he main benefit of this is to make sure that the point motors will not be positioned where there is framing below the plywood baseboard. I knew that I would need to expand the baseboard on the approach to the helix so with the paper plan in situ, I was then able to measure and cut the timber to size.

The triangular extension is built
The extension immediately becomes a workbench!

I then took the opportunity to position the oval rings which will make up the second helix, screwed them to the base and then drilled 12mm holes right through all of the support lugs. This will make the helix construction easier and ensure that all of the holes are aligned accurately.

Finally, I began laying the pointwork at the eastern end of the storage sidings, the southern end is already complete so as soon as the eastern end is complete I’ll lay the flexi track in between.

The pointwork leading into the base of the helix.

Yet another tidy up.

I’ve lost count of the number of times that I have had to stop and tidy up before carrying on with the next phase of construction. In an ideal world, I would have the room or building site, a separate room for storing materials and a workshop for cutting timber. In the real world, it’s all in the same room so I have to clear an area for working in, the materials are stored on the other side of the room and any cutting takes place somewhere in between. It can be a bit awkward, building in a store room / workshop but as the build progresses, the amount of space increases as the materials and components are used up.

Permanent legs fitted
Angled section built

Following on from yesterday’s construction of the first of the upper baseboard frames, I fixed the framework into position with permanent supports at the front. I also finished off the angled section which will support the track bed as it leaves the helix.

I then moved the framewood and plywood from where it has been stored on the eastern side of the room to its new home on top of the new framework. This has cleared the way for the next bit of tracklaying, the second storage yard which will, along with the second helix, form power district 2.

Benchwork cleared ready for the next stage.
A bit of working mess!
Tools, track and cable fill the centre section.
New area for storing materials….
and doubling up as a workshop!

Interestingly, the installation of the upper level framework has immediately helped me to start visualising how the scenic section might take shape which has in turn inspired me to get cracking with the next section!


More bench work!

In my previous post, I described how I had started on the second storage yard which is part of power district 2. Today I put together the benchwork which will support the scenic section above the first storage yard. This is purely so that I can store the building materials that are currently sitting on the low level benchwork on the opposite side of the room. I am now able to shift everything on the eastern side of the layout so that I have enough room to construct the second storage yard and adjoining helix.

The framework is made from 4″x1″ softwood (95mm x 20.5mm in reality) and sits directly above the lower bench. The crossmembers are spaced at approximately 400m (16″). An inverted ‘L’ girder, which is attached to the studs in the wall, gives support on two sides and temporarily I have fixed timber supports at the front. I am thinking of using threaded bar for the front supports so that there is a facility for levelling the structure. The framework still needs to be fixed to the wall supports, another piece is still to be attached to the helix end at 45ยบ to give support to the track leaving the top of the helix and the front edge supports still need to be constructed.

Inverted L Girder wall support.
Western wall support.


Additional lower level brace.
The ladder frame takes shape on the floor.

The upper benchwork in place with temporary supports.

Power District 2

After completing the testing on Power District 3, it was time to make a start on its mirror image, Power District 2. I had previously prepared all seven sets of points by soldering the feeder wires to the rails and by attaching pieces of track which are 93mm long to the “toe” of the points. These pieces provide the correct spacing of 67mm between the storage tracks. I had also previously soldered wires to the tortoise point motors so with everything pretty much pre-fabricated, I was ready to go. I drew a straight line on the baseboard to align the pointwork and then started with the first set of points. As before, it was a matter of placing the point and then marking the position where the hole for the point actuator wire would go. That hole was drilled out with a 13mm spade bit and the point was then positioned and pinned down with Peco track pins. The remaining six points were added in exactly the same way before I drilled holes to pass the feeder wires through the baseboard. I then pulled the wires through to the front of the baseboard and connected them to the connector blocks there, completing the work for the morning.

After lunch, it was time to fit the Tortoise point motors by crawling under the baseboard, cleaning up the underside of each hole where the drill bit had broken through the plywood and then marking the holes for the fixing screws. It’s a simple process to thread the actuator wire through the hole in the tiebar of the points and then tighten up the fixing screws. I then pulled each bundle of eight wires through to the connector blocks at the front of the baseboard and made the connections. As with the points, it was just a matter of being methodical with all seven motors.

Finally, I set up an eight way accessory decoder (A Bill Cuthbert designed board) in a temporary position and wired in the Tortoise motors. I then tested each motor to ensure that the motors worked and were going in the correct direction, two of then needed to have there throw adjusted by moving the fulcrum on the side of the motor. When that was done, I then configured the points in the Train Controller software and tested again. All that remains now is to cut the excess actuator wires so that rolling stock can run over the track.

Beginning of the second storage yard