The City on the Edge of Forever

city edge of forever startrekNo, this isn’t about a StarTrek themed model railway — how cool would that be! — but a quick tip on how to stop views into a different time and space from spooling your layout.

Last weekend, I was ambling around a local model railway show and looking at the glorious layouts before parting with some hard-earned cash at Squires on a tool I didn’t know I need thirty seconds before 🙂 when the impossible lurched into view.

A lovely loco was trundling around the track, it passed through beautiful cutting and slipped between some delightfully well-made trees. I and the other viewers were enthralled by the little train and its beautiful surroundings. 

But then it came to the edge of the layout and approached the portal that would take it off to the fiddle yard.

And there it was, through the tunnel entrance another world beckoned. A world inhabited by giants, whose hands swept up the trains as we watched them. One moment we were looking at a carefully constructed scene of railway life from the past, the next your eyes alight on a gap in the space-time fabric of your tiny world revealing the real larger reality beyond. The lovingly created micro-illusion of the model railway came crashing down.

If you have a tunnel portal through which your trains pass on their way to and from an off-stage fiddle yard you’ll know the problem. Light from the rear beaming through the portal or the fiddle yard is visible through the tunnel.

In some circumstances, you can cloak the portal from view or have a long curving tunnel with decorated walls hiding the exit off the main baseboard. But sometimes you’re stuck with an exposed tunnel portal that just leads off the set.

It’s like peeking through a doorway and seeing a whole different world or time, as Kirk and his team faced in the classic City on the Edge of Forever Star Trek episode.

What to do? 

How can you hide the world behind the backscene from viewers of the miniature world of your layout?

While visiting the Warley model railway show, I saw took some pictures of one practical solution.

It’s on the Longnor layout by Hugh Williams, seen below.

Hugh has hung flexible flaps just inside the entrance of the tunnel.

model railway tunnel tip

These hide what’s going on in the background but being flexible allows rolling stock to pass through easily, the flaps just lift as the train passes through.

This collage shown of the portal on Longnor (above) shows it in place and an engine passing through to illustrate how it works. Click a photo for a larger view.

Rubber or paper strips painted a dark colour, are attached to the tunnel ceiling. Weighting them down slightly at the bottom will keep them in place.

As an added extra tip, you could also attach brush hairs to the flaps. Doing so adds nothing to the operation of the flaps or visual benefit but it will give your rolling stock a dust-off and keep them clean.

It’s a simple, elegant solution, and easy to implement. 

Now “let’s get the hell out of here”* as Kirk would say, and go and try it on your layout. Let me know how you get on. Even better, join the MRE Community and share photos of your tunnel entrances.

> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.


  • For those that haven’t seen the episode, “Let’s get the hell out of here!” was Kirk’s closing comment at the end of City on the Edge of Forever. It perfectly captures the emotion of the tragic ending to the award-winning episode.
Founder of ModelRailwayEngineer, Andy Leaning

Andy is a lifelong modeler, writer, and founder of He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.

Afflliate disclosure:The links on this page may take you to carefully selected businesses, such as Hornby, Amazon, eBay and Scale Model Scenery, where you can purchase the product under affiliate programmes. This means I receive a small commission on any orders placed although the price you pay does not change. You can read my full affiliate policy here. I also sell my my own ready to use, pre-made and painted buildings and terrain features. browse the range.
  1. Strategically placing trees and bushes also helps, but this flap idea is great.
    Ensure that the material is flexible and light enough to not hold the train and wagons back or off the track. Also that it will not snag on fixtures such as stacks, whistles, goods etc.

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