TECHNICAL

COUPLINGS

 

Most Welsh narrow gauge rolling stock is relatively small and proprietary coupling systems, disproportionately large and, we thought, unsightly. Early on therefore, we developed a centre buffer system with fine chain couplings. This has the disadvantage of not allowing coupling or uncoupling during exhibitions and we always run fully formed trains. However, rolling stock appears close coupled and, we think, more realistic.

 

The Mark 1 version required a track pin mounted horizontally in the buffer beam with a fine wire hook mounted underneath at both ends. The short length of chain lightly glued to the hook one end of each vehicle is then connected to the free hook on the next vehicle. Some goods stock like the GVT granite wagon didn't need the centre "pin" buffer, just the hooks.

 

As the layout is an end-to-end rather than a tail chaser, train movements required some propelling. It took us a few months to work out that the frequent (embarrassing) derailment whilst propelling was caused by buffer lock. The solution was to upgrade all centre buffers to a Mark 2 version. This uses the same horizontal track pin with a 2mm x 1mm piece of plastic (cut from razor wrapping) glued vertically on the outward face (pin head), with the long edge horizontal. This gives the extra width to prevent inter-buffer fouling and seems to work. Some unfinished Mark 2s are still "Gillette" blue.

 

ELECTRICAL AND CONTROL

Cader_Track Plan B

The train control system to the Scenic board is a simple 12v analogue feed from a single point adjacent to the Signal Cabin. Variable power is supplied by a Gaugemaster Combi, hand held from the front of the layout.

 

All points on this board are operated by under-board or concealed surface mounted point motors, switched from a bank of three proprietry passing-contact switches, powered by the Combi 16v supply and a proprietry capacitor discharge unit. The points at both the Gregennan (A) and Cabin (B) ends of the Platform line are operated together by one switch.

 

The fiddle yards on left (Tyrau Mawr and Cregennen) and right (Dolgellau) are powered by the same 12v Combi supply and are switched in or out as required. This combination allows realistic movement of four separate rakes of stock, one at a time.

 

For exhibitions, the layout is operated on a total cycle of fifteen train movements; twelve representing reality and a further three to propel stock back to its starting point.  Shunting isn't possible. Whilst this can become tedious for the operator, it does allow concurrent conversation with vistors and constant movement. Each stock movement is defined in binary form by:

 

    1. Move number. (1-15)    

    2. Three point settings

    3. Three fiddle-yard on/off settings

    4. Position of the R/F selector swicth on the Combi controller

 

Settings for each of the fifteen movements are recorded on a credit card sized aide-memoire as a line like:

 

    # PPP FFF C  

 

where each letter is either 1 or 0 (switch set up or down) except "C", the Combi switch, which is set "R" or "F - for example "13 011 010 R". All the operator has to do is remember the next stock movement number and set the switches accordingly.

 

There is a choice of five roads in the Dolgellau fiddle yard which allows a limited exchange of trains to display a greater variety of stock. Fiddle yard points are operated by hand in view of the visitor in order to better display stock rakes.

 

A

B

TE 001

TE 002