Cwm Bach

A 1980s South Wales branch line terminus, modelled in 7mm scale

 Cwm Bach is going on the road - come and see it at the Gauge O Guild Spring Show at Kettering, in March. Please check the Events section for more details.

  I'm selling most of my steam era stock. I also have a collection of N gauge stock to sell (to fund my O gauge investments!). The full list can be found in my eBay shop.

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Layout view
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 About Cwm Bach

Cwm Bach (translation: little valley) is a fictional location, somewhere in the South Wales valleys, nominally a few miles from Pontypridd (but not to be confused with the real Cwmbach near Aberdare).

In this 7mm scale/O gauge model, it's presented as a run-down late 1980s single track branch line, with a small platform and a DMU service. The line was once double-tracked and continued through a tunnel but that was closed many years ago and only remains today because it's a reversing point for freight (mostly civil engineering and wagon repairs). There's no space for a run-round loop, which necessitates some shunting and there's generally an 08 or two to be seen. As well as the regular DMU service, Cwm Bach also sees the occasional visitor on a test run from Cathays Works or Cardiff Canton depot. Watch out for a 37, a 33 or a 56 either "light engine" or with some interesting short trains as well as an occasional steam special...

What started out as "just a micro layout with a shunter and a few wagons" has grown into something much more detailed and complex with an extensive collection of locomotives and rolling stock.

Meet the 4cm tall people who live and work in Cwm Bach.

 Technical details

  • 3m x 0.45m (approx). 2m scenic section.
  • DCC controlled track, DC points and lighting.
  • DCC control with DCC++ (running on an Arduino Uno) a Digitrax DCS52, optionally with JMRI (on a Raspberry Pi 3B) a Digitrax LNWI and WiThrottle (Apple iOS).
  • Peco track.
  • DCC Concepts switches for points and signals.
  • Routemex colour light signals.
  • A variety of manufacturers' stock (mostly Heljan and Dapol, but also Ellis Clark).
  • Time to build: 3 years (so far...).

 Still to do

Although Cwm Bach has been exhibited, no layout is ever "complete" and, at the time of writing, I still need to:

  • Build and install the home and position signals at the end of the platform.
  • Finish the lever frame.
  • Add switches to the lighting circuits.
  • Add some more scenic details (e.g. guttering on the houses).
  • Add some more bushes and some longer static grass for more weeds in the sidings.

I'm also thinking of adding a small extension board on the front of the layout and building a footbridge over the sidings, at the point where the two scenic boards are joined.

Follow my progress on RMweb.

 News

What's new in the valley?

  • September 2025: Orders have been placed for modern image stock to run a contemporary service, as an alternative to the normal 1980s/90s setup. Initially, there will be a Heljan Class 153 in Transport for Wales livery and this will be joined by some Dapol Class 66s, once released. I've already bought some Dapol Coalfish wagons in EWS livery to run with the 66s...
  • September 2025: Also on order, is a Railfreight-liveried split headcode Class 37 and a Gulf Oil TTA wagon.
  • November 2025: The Transport for Wales Heljan Class 153 has arrived and makes a nice change to run something more modern.
  • November 2025: a Heljan Class 128 DPU has unexpectedly been added to the fleet, after I was impressed with the customisation by Vincent Burke (Protoneo).
  • November 2025: I've been working on customising my GUV and the Mk1 support coach for the Black 5, adding transfers from Railtec.
  • December 2025: I've picked up one of the last available new Dapol 08s in EWS livery, to be converted to 08904 in 2006 condition.
  • December 2025: A little Peckett Type E has arrived, with Father Christmas at the controls, a Dapol Christmas coal wagon, and the Brains Beer delivery. Nadolig Llawen all!
  • January 2026: I've managed to get hold of a 2-car Heljan Class 117 DMU in Network SouthEast livery. I'm still deciding whether or not to get a three car as well to convert to a 116 and paint in 1970s white and blue stripe livery.
  • January 2026: I've been working on the scenic details, getting the layout ready for its next exhibition.
  • January 2026: 25035 is coming on well, and should be on its way to me in time for the Kettering show.
  • January 2026: All of my steam stock (except the Black 5) will be listed for sale. The Black 5 is likely to get a Digitrains real steam conversion... but not before the Kettering show.
  • February 2026: Cwm Bach is featured in the Gauge O Guild Gazette!

 Events calendar

Here's a list of shows where Cwm Bach has been or is due to be exhibited:

Date Location Notes
7/9/2024 Olney Model Railway Club Show cancelled
28/9/2024 Kempston and District Model Railway Society 10:00-16:30 at Kempston East Methodist Church, 227 Bedford Road, Kempston, MK42 8DA
13/9/2025 Olney Model Railway Club 10:30-16:30 at The Olney Centre, High Street, Olney, MK46 4EF
7/3/2026 Gauge O Guild Spring 2026 Show 09:30-16:00 at The Arena. Kettering Leisure Village. Thurston drive. Kettering, NN15 6PB
25/7/2026 Letchworth Model Railway Society 10:00-16:00 at The Priory School, Bedford Road, Hitchin, SG5 2UR

If you would like me to bring Cwm Bach to your exhibition, please get in touch by email.

 Additional information for Exhibition Managers

(The following information is also available in a downloadable exhibition flyer.)

You can see the technical details above - but the layout can be operated from the front or rear, and requires approximately 3.5m x 1m of space.

Here's some photos from the layout's exhibition in September 2025 (there are still a few things on the to do list).

Cwm Bach set up and ready for exhibiting at the Olney MRC exhibition in September 2025

Cwm Bach set up and ready for exhibiting at the Olney MRC exhibition in September 2025.

Cwm Bach looking towards the station and sidings

Cwm Bach looking towards the station and sidings.

Cwm Bach looking across the station throat and towards the traverser

Cwm Bach looking across the station throat and towards the traverser.

There are more pictures of some of the layout detail on the People of Cwm Bach page.

Mark Wilson (the creator and owner of Cwm Bach) is a member of the following model railway organisations:

Olney Model Railway Club (OMRC) Gauge O Guild (GOG) Diesel and Electric Modellers United (DEMU)

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