How to build a scenic tunnel for your railroad

The very talented Martin has sent in this superb ‘how to’:

“Here’s “My way” of making scenic items to place on model railway layouts. I produce many different models usually which have some form or rock face, but not all are landscaped the same although I do tend to put plenty of grasses & many bushes on my models.
This project is a single track tunnel entrance designed to fit in the corner of a layout with the track running behind the back scène to a ‘fiddle yard’.

First I use a type of insulation foam which is used to insulate houses, the off cut’s are ideal to make models. (Please excuse my untidy workspace).

Picture shows a couple of blocks of foam which I will glue together.

I almost always use PVA glue which I find very good & cheap.


Once dried I pick up my sharp kitchen knife and trim the foam.

Having obtained a readymade resin tunnel portal used on this project, I marked out on the foam the tunnel and carefully began to carve the foam.

On many occasions I do not use a portal but carve my own into the foam, this model I decided to paint a resin postal to use.

The roof of the tunnel was shaped by using a desert spoon.


Once dry, I paint the rocks with a very watery black into the cracks.


Then I use a light emulsion on an almost dry brush to bring out the highlights

The tunnel portal can be then glued onto the foam by using a strong contact adhesive bought from the Poundland shop in the town centre. The model is now ready to

Start applying the landscaping. This is a matter of taste and I vary my models by the use of a variety of types of grasses & bushes. Most of my materials are Woodland Scenics,

Although I do sometimes use other makes. On this model I have chosen to first apply an olive coloured grass onto the rock embankment.

Then I applied a summer ‘Static grass’ by the use of an electric applicator

With short static grass, the static effect of making the grass stand up is not very effective. But when I use 4.5mm & 6mm grass the effect is very lifelike.

The next job is to apply a variety of bushes onto the model, again by PVA glue

All that is left to do then is to give the model a spray of watered down PVA glue (always remember to run some clear water through the spray  when you have finished as

It can set in the nozzle & ruin the spray for future use).  I then sprinkled some Woodland scenics coarse turf onto the summer static grass and a little on the rocks.

I usually add a row of various bushes along the back edge of the model

That is how I make my models, I hope that it gives you some ideas? Whilst this is drying – Here’s one I made earlier where I carved the portal myself.


Martin – I think it’s a suberb ‘how to’. Thank you from all of us.

And for those of us not as talented as Martin, don’t forget my favourite resource where there is lots more stuff like this.

And if you’re heading off to ebay to buy some tunnel material – have a peek at the ‘ebay cheat sheet’ first. It’s here.




55 Responses to “How to build a scenic tunnel for your railroad”

  1. david says:

    Exellent job you have done there Martin…well done

  2. Len Lainsbury says:

    Beautifully detailed explanation and a lovely final result. Very inspiring, and something to look forward to in the coming winter months when we can`t get outside to try other tasks in our incredibly fulfilling hobby. Thanks Martin, and everybody else who contributes, especially Alistair for his untiring efforts.

  3. Robert Isberg says:

    This look better then the finish product you bay from Heki or Bush.

    Thank you,

    Robert Isberg

  4. johnstuf says:

    Martin, thanks for sharing your handywork. I have not yet gotten into scenery myself but I will remember your excellant details.

  5. Martin says:

    Mmm looks ok but a couple of points to mention, you forgot to add that I paint the models with a grey water based emulsion paint. You put 2 pictures of the static grass applicater & at the end where I commented “heres one I made earlier where I carved the tunnel portal” you did not show that pic. but went straight to the actual model.
    People maybe wont notice. hope you didn’t mind me passing comment?

  6. John Roetman says:

    Great way to make a tunnel. I will save this with the other tips in my personal model railroad file.
    John R

  7. Trevor says:

    Martin you have done an excellent job. In the past working with foam didn’t appeal to me as I saw it as unrealistic. However, you have now converted me. Could you please send some more of your’e great work.

  8. Al says:

    Sorry Martin – I’m always in too much of a hurry! I shall add them.

  9. Hey Al,

    It is a great job one heck of a lot of work too even with foam. I like it.


  10. Barry Clay says:

    Wonderful effect Martin,foam is such a good core material for model railroads,thank you for the detailed explanation.

  11. david says:

    well done , a very good tunnel,excellent, please show us some more things that you have made for your models thanks.

  12. Martin says:

    A few people asking for some more pictures, Al did already kindly show some pictures of items that I made. I am making a stock of items to hold a stall at Rochdale Model Rail Fair on 5th/6th November in UK. It is a new venture now that I am in my retired years. If anyone wishes to keep up with my additions you can see them on this site;
    Thank you Al for sharing my hobby with others, you have a great site.
    By the way just a bit of advice for anyone wishing to try the foam modelling – DO NOT USE expanded poystyrene for this type of modelling, it is the pink type. And when carving the rocks, do not just cut pieces out, prise pieces off and it will look more natural.

  13. Barry Palmer says:

    Martin very well done. I’ve always preferred working with plaster and cloth for the mountains but I’m going to do my next layout in foam because I like the results of your work.

  14. BOB says:


  15. dennis says:

    Working on a layout here in S. Carolina. I am also making great use of extruded foam for mountains. Love your tunnel idea and I will defintely be trying this one out.

  16. Sheila says:

    Since I like to use foam insulation on my layouts…this was very informative. Great tutorial and instructions.

  17. George David Snow says:

    Very creative – can probably be adapted to any scale – I’ll use N scale when and if I get a RR. I’m very short on space! Thanks for a great How-To Article!

  18. alan says:

    a very nice realistic effect foam of most types make excellent scenic good job Martin

  19. Dennis says:

    Most model railroaders build tunnels over track that has already been laid. Then it is difficult to get an detailed interior. It would seem you could use the carving technique to do a blasted rock interior. You could also incorporate a wood line tunnel too. I can see how this method of carving the tunnel to go in place after the track is laid would be helpful to get realistic details inside the tunnel. Then you could build your foam mountain by incorporating the completed foam tunnel into the layers of foam that make up the mountain side.

  20. Jim Stevens says:

    Hi, I too am using foam for my mountains and tunnels. The foam I am using though is the foam from an old couch and chair that I found sitting out for the garbageman to take. I figured it is not only a free way to design, but it is also recycleing. I am taking pictures as I go along and I am looking forward to posting themk here and on the other model sites I am on.

  21. Edward McDonald says:

    ED says

    thank you for showing me how to build asenic tunnel great job.
    I have plastic building kits to glue together what gulue is best ED

  22. Martin says:

    In answer to Edward McDonald; For glueing plastic model kits I use ‘Contacta’ polystyrene cement marketed by Revell. No doubt there are plenty of choice in US.

  23. John says:

    I totally agree with Bob when he said that a lot of pics showing the actual, and not paragraphs, makes it a whole lot better when you try to build or model something! KEEP UP THE GOOD WORK!!

  24. Max says:

    creative and makes the help easier when approaching such fit and finish!

  25. Luke Kelly says:

    Great creativity. I think you should sell these on eBay as they look superb.
    I would definitely buy one.
    KEEP IT UP!!!!

  26. Richard says:

    They say a picture is worth a thousand words. WOW!
    This is a masterpiece to be proud of.


  27. Martin Cariss says:

    Great work from my namesake! Particularly the way to highlight the carved rock formations.
    One or two points to add, if you don’t mind: this type of insulation foam is very cheap to buy here in the UK, and is cut by builders with fine saws and doesn’t break up, I have used a fine blade in a jigsaw for a fast cut, using a kitchen knife looks like an accident waiting to happen!
    Also always use a solvent FREE adhesive as other types WILL eventually melt it! As another contributor mentioned for small areas “Oasis” florist blocks are ideal and from time to time can be found in discount stores at a cheap price in the UK.
    Keep up the good work Martin, and also Alistair for passing these tips on.

  28. Semus says:

    Sir, I am new to railway modelling. However in Aldi yesterday I noticed bags of crushed granite I think.Anyway not too expensive , a fair sized bag which could be shared ,and glued under track as a very realistic ballast. Forgive me interrupting in what may be a stupid idea.
    Secondly I have a number of locomotives belonging to my adult sons that have jamming piston rods and slip of plastic guides , and others with twisted and or missing valve gear. What is the best to do with these.Just sell on E Bay as broken and buy something other.

  29. Chris g says:

    What type ov paint do u use on foam and plastics mate

  30. Marion says:

    I am confused as to “expanded” and “extruded” foam. Depending on the company, the extruded comes in pink, blue or yellow. That is what I plan to use for my base, as it is less likely to melt under the glue and paint, and is great to carve. You tell us not to use the pink foam, but in your pictures, the foam is pink, or is it my computer? What kind of foam did you use for the tunnel?

    Your modeling techniques are wonderful, and I will certainly use your tunnel idea. My husband and I are beginning at ages 76 and 77, and are very excited to get going on the scenery. He is painting our new room just now, then he’ll begin the fun of building the benchwork while I continue with putting together structures, experimenting with rock-moulding, making trees to go with the ones I’ve purchased, and learning to work with water effects…Thanks so much for sharing your ideas!

  31. Tony Nguyen says:

    Very clever and exciting work! I hope I can do that. TN

  32. Sid says:

    Brilliant work, well done, The photo’s are clear and easy to follow too as is the explanation, Well done !!.


  33. Michael Ankerson says:

    Great job…

    Martin very well DONE…


  34. Jeff Keene Sr says:

    Great job, Martin! A real keeper for future reference! Thanks.

  35. Chris poppe says:

    I really like the way the finished tunnel looks. The photos and explanation of the way you created it are excellent. Thanks!

  36. Bud says:

    I have made my hills and mountains in the past using hydrocal and newspaper, which can be a messy process. You also dont have a long time to work with the hydrocal before it “sets up”.

    I really liked your demonstration of using carved foam to form mountains and hills. This is an excellent idea giving the modeler plenty of time to work the foam to satisfaction. And with proper painting and landscaping your finished product looked really great. Thanks for all of your time and tips, this opened my eyes to other possibilities.

  37. StJohn says:

    some really artful sculpting there Martin….yer good…bookmarked your paga and I am going to finally try this just because you showed us how….
    and I agree with Luke above…these would make BIG $$$$ on ebay. you should defo look into that….shipping ‘light weight’ stuff is cheap…

  38. Bonny McDaniel aka Grannytoot says:

    Martin: I, too, would like to know why not to use the pink foam as that is the only type I can find in CA. Love your carving and the ideas I picked up from your photos and very curious if you live near Rochdale as that is where my great grandfather, Robert Schofield, was born. He came to America in 1848 and I’ve always wanted to go to Rochdale…maybe won’t get there now (I’m 77) and have to content myself with working on my first model railroad layout!

  39. Ross Johnston says:

    What a great srtep by step guide to constructing a tunnel. Thankyou and well done!

  40. Ian Mc Donald says:

    nice work you made it look easy.

  41. paul Otway says:

    nice work

  42. Roy says:

    Great work, wish i was that artistic.

  43. charlie says:

    Excellent, Great tip. Thanks

  44. Tom says:


    I just have to ask this. In the next to last picture … it look like someone is lying down in the tunnel. Maybe my eyes are not as good as I thought.

    The tunnel is truly a work of art. A Masterpiece! I surely like the use of the foam. Or maybe better, your use of the foam.

    Martin, would have some video you could share of your railroad? Sure would like to see it.

    Martin thanks for the pictures and of course Al thanks for the archive.

    Best regards,


  45. Tom says:


    ( I took keyboard 101 you would never guess it … oh well LOL)

  46. THOMAS says:


  47. Matthew says:

    I read the post that said the person was using foam from a couch? I tried that once but found I had to soak it in Elmers glue then let it sit to dry in order to shape it and have it stand stiff.

  48. Willie Kerr (Glasgow) says:

    Excellent stuff, good tips too.

  49. chris says:

    Excellent job and superb tips; Thank you

  50. Charles E. Adams Sr says:

    Martian, you are very gifted

  51. Rod Mackay says:

    Semus, regarding your problems with loco valve gear, you don’t say what manufacturer’s trains these are, but there are dealers in spares for Hornby, such as Blackwells of Hawkwell, who do a large range of spares and you can also find blown-up diagrams of most Hornby locos on their website so you can identify the damaged parts. Quite often the damage is simply caused by kids picking models up by the gear and bending it in, compare one side with the other to identify any parts that may have been damaged or pushed out of shape. Worth a try to restore before resorting to e-Bay. Good luck!

  52. GOPAL DAGA says:

    Hi Martin,creating tunnel, as you have done is simply excellent. Very economical & realistic. Thanks for your illustration. It’s very very inspiring and save lot of money, if you buy branded stuff. Pl keep it up. Regards,GOPAL DAGA!KOLKATA , INDIA

  53. Patrick Potter says:

    Martin, I want to thank you for this information, I’m going to put this in my files for later use, this will be very helpful.

    Again, thank you

  54. Sublime. Truly. Keep up the great work sir.

  55. Dave G says:

    Very nicely done and a well presented, easy to follow tutorial!

    Thank you.

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