by David Powell

00 ‘Out of the Box’ DCC, BR Scottish Region 1960s


Invercrasey, is an 00 DCC ‘shake the box’ essay in modelling, and is the result of Mick Moignard introducing me to DCC sound. My long term ‘serious modelling’ 7mm Colonel Stephens genre imaginary extension to the Criggion branch on the Shropshire and Montgomeryshire was put on hold and covered in a dust-sheet in its current home in the loft when the local planning authorities reallocated me the smallest ex-bedroom in the house a modelling den. Invercrasey is not serious modelling, well not much. The basic requirements are to get something running reasonably quickly by exploiting some of the excellent RTR products now on the market from the Hornby and Bachmann. Track is code 75 Peco but with the chunky sleepers either side the tie-bars cut back to line up with the rest of the sleeper base to help disguise their source.

The setting is a (yet another) West Highland port, period 1960s when steam and green diesels shared the traffic. With space restricted the project to a 9’6” by 8’ L-configuration. Invercrasey is not designed for exhibition, but it is being constructed so that it could be relocated at some time in the future.

It is designed for operation. In addition to a main platform and a bay for passenger traffic, there is a small 3-road goods yard for shunting and the yard has its own run-round if the station is occupied. There is a short kick back from one siding which doubles as the DCC programming track. There are some loco facilities and, in addition to the cassette dock representing every where on the ‘main line’, there is a second dock from the line which feeds the MPD which intended for short cassettes which can represent and feed in off stage industry or even a branch line.

Turning to current work in progress; from the photo, you can see the layout’s foundation. This comprises three 4’6 x 2’ open 70mm x 18mm frames on 35mm square legs standing on floor levellers. On these frames sit the four 2’ wide baseboard modules. These modules are constructed from 100mm x 18mm prepared timber with 9mm ply tops. Two are 4.6” long and two 3’. Just in shot to the right is the 4’6” Board 1 (station platforms) which includes a small dropped triangular extension to incorporate Loch Crasey lapping a section of the harbour wall.

Standing on its rear edge and clamped to the frame is the three foot board 2, the station throat, showing its 9 Cobalt point motors. This disproves the myth that there is not much in the way of wiring for DCC! Note the use of n-gauge track as pairs of local power distribution bus and the white painted underside. The reason for the board being on edge is so that I can positively check the wiring colour code conventions while working on board 1 to the right. This is about to have its point motors fitted before adding board’s district power cu-out and the n-gauge local power bus track.

One tip here, once the point motors, local power cut out and bus are installed I take a digital photo of the underside of the board, and then download and import the photo file into Power Point so that I can reverse the picture. This is then printed on an A4 sheet to give me a picture of what is immediately under the 9mm module top when I come to drill the holes for the dropper wires from the Peco track.

To the left is the trackless three foot board 4 which is not only the main supports for the train cassettes but also provides a handy ‘work-bench’ for work in progress. The already wired up and tested 4’6” board 3, (locomotive stabling facilities and cassette docks) is squatting in our guest room to give me more space for work in progress.

Each layout board has its own district power cut out which is fed from the common DCC bus and each board has its own socket on the small white board edge panel which connects to the 9 volt DC point power bus. The power source for the point motors is a recycled KPA4 (lap top?) power adapter. The white edge panel for board 1 can be seen to the right of the photo. Each of these module panels has a power on-off switch and the indicator LED and cut-out reset push switch for the local district board.

The point control panel is split to manage the points on boards 1 and 2. These panels were made so that they could be wired up before being bolted to their respective mother boards. They are tilted at a slight angle by including a length of 1” wide balsa model aircraft trailing edge triangular section between the control panel and the module edge.

The shelf currently holding the Digitrax DCC controller on module 1 can also be slung on similar supporting screws on boards 2 or 3. Board 3 also has a built in mini panel to control the turntable. The main power bus connectors which join the boards are the same as on the DCC controller. Thus, it is possible to power up, test and operate each board independently or as pairs.

Each layout board has a pair of 6” by 2’ end protectors so that I can work on the individual layout boards inverted, or clamped on edge on the sub-base (as Module 2 is in the photo) or in the normal position on top of the foundation unit. The foundation unit also provides a solid level base to plug two boards together to test the line of tracks and power. The boards are lined up using brass pattern makers dowels and sockets.

The next task is to fit the Cobalt point motors to board 1. Based on my experience with boards 3 and 2, the process I have developed for the Cobalts is as follows. The 7mm hole lined up under the point tie bar was drilled as suggested in the instruction before the point was laid. However, I just couldn’t get on with the Cobalt template provided for drilling through the base board to locate the under board point motor mounting screws. With my slightly wonky left eye, I just couldn’t get perfectly vertical holes. My method is as follows. Unless the point is already parallel with an edge of the module board, I first mark and cut a piece of paper or card with the angle of the point tie bar with reference to a convenient straight base board edge. I then invert the base board and gently drill out the tie bar hole from the rear using a large countersink – but not so deep that you bore through and attack the underneath of the tie bar! The resulting cone shaped hole makes it so much easier to see through to the hole in the tie bar. Mark the underside of the board with axis of the point tie bar using the piece of card cut out earlier. Then, insert the Cobalt plastic fulcrum, mount the connecting operating arm and secure the operating arm to the point motor. This uses the smallest fiddliest screw ever devised by an Australian. I resorted to adding a bit of blue-tack to the proceedings to help hold the screw while I lined up my smallest instrument cross-head screwdriver. Holding the point motor, poke the secured connecting arm through the tapered hole, line up the point motor with the reference line and mark the position of one of the screws which will be fixed in one of the four underside mounting slots. Withdraw the point motor. Drill out the first fixing hole, re-present the point motor and fix it with the first mounting screw. Mark the remaining 3 holes, remove the point motor and drill these out. Re-present the point motor again and secure with all 4 screws. Now you are ready to adjust the final position of the point motor, wire-up and test. The Cobalts are a bit noisy and can be mounted on rubber mounting pads, although I haven’t tried this method.