That’s just ducky

My post about my first sketch for a model railway based on Ferguson Avenue in Hamilton generated a fair bit of feedback about duck-unders. I’d like to thank everyone for the thoughts, and provide a few thoughts of my own.

My layout sketch includes two duck-unders, highlighted here:

I envision operators using the green duck-under most frequently. I’ve added the yellow one primarily as a means of quick/alternate exit from a long aisle in case of emergency, but it’s also an optional shortcut for the more nimble. So let’s set that one aside and focus on the green one.


First, I’ll admit I hate duck-unders. I’d rather not have one. Unfortunately, if I want to model Ferguson Avenue in S scale in this layout space a duck-under is pretty much unavoidable. The continuous-run nature of the plan dictates that at some point, one is going to have to get inside the big, closed loop.

That said, I’ve built layouts with duck-unders before, and there are a number of factors to consider. These include:

  • How often will the duck-under be used in an operating session?
  • How high will the benchwork be?
  • How deep is the span being ducked under? (In other words, how long do you have to duck before you can stand up again?)
  • How wide is the opening? (In other words, do you have to enter the duck-under head-on and waddle to the other side, or can you stand sideways and then swing your torso under it?)
  • How is the duck-under finished? This includes the shape, the materials, any protective padding, and so on.
  • Does the duck-under include aids such as handrails or a chair on casters?

These are all things I would consider if I build this layout.


On a previous layout, I incorporated a duck-under to reach a staging area and I finished the opening with masonite panels on all sides. I used glue on the masonite panels – I was careful to not include anything such as screw heads that might catch clothing – and I finished the duck-under entrance at both ends by curving the edges to remove any sharp corners. It worked well – one could actually slide one’s back along the duck-under while getting from one side to the other.

Admittedly, I was much younger than I am now. That said, it was also much lower than what I envision for Ferguson Avenue. The span was much deeper too.

While I have not drawn benchwork edges on my Ferguson Avenue sketch, I would make the green duck-under as shallow as possible – ideally, not much deeper than the double-track roadbed. I would brace this span like a through girder bridge, with benchwork framing above the track’s subroadbed to maximize the clearance height while providing the rigidity such a span would require.


I will also consider whether a swing-out gate is a better option. My friend Richard Chrysler had a beautiful gate to enter his layout:

Richard Chrysler’s swing gate in the closed position. This scene – the CNR Hagersville Sub’s climb up the Niagara Escarpment – greeted visitors to the layout.
Richard Chrysler’s swing gate in the open position. Once inside the layout, one did not have to pass through the gate to operate, as this Niagara Escarpment scene was plain track – essentially, an unfolded couple of loops of the helix that connected the two levels of his layout. On the downside, from the inside of the layout one could not confirm that there were no trains on the track here before opening the gate.

Rich’s gate featured a steel frame, welded up by a mutual friend of ours. (I won’t name him here, because he probably doesn’t want to go into the business of building swing gates for others.) It was very reliable because the steel frame did not move with seasonal changes in temperature or humidity.

That said, I do have two things to consider about such a gate.

  • First, there’s the issue of anchoring the two pieces of benchwork to either side of the opening to ensure they maintain proper alignment. I have a fully-carpeted layout space and I’m not about to drill through it into the floor to anchor the benchwork. The alternative is to connect the two sides of the opening, either with a step-over at floor level, an arch overhead, or both.
  • Second, there’s the issue of the inner track on the turn back curve. This is used as the transfer track between the Stuart Street Yard and the switch crew working the Ferguson Avenue freight shed and local customers. I would not want to open this swing gate if there are cars standing on this track: That would be a recipe for disaster.

I hope this post eases the concerns of those who commented about duck-unders on the initial sketch. Rest assured if I can’t resolve this to my satisfaction, I will consign Ferguson Avenue to the “interesting thought experiment” bin and plan something else…

Published by Trevor

Lifelong model railway enthusiast and retired amateur shepherd who trained a border collie to work sheep. Professional writer and editor, with some podcasting and Internet TV presenting work thrown in for good measure.

15 thoughts on “That’s just ducky

  1. Hello again Trevor. Just a thought. Could you eliminate both duckunders and create a swing bridge or lift bridge at Family Packers? It looks narrow enough from the sketch. Sure, you would have to anchor the building down and temporarily move cars but maybe something to consider. Just my two cents. I am enjoying your thought process as you go through this.

    Liked by 1 person

  2. Trevor, I used an office chair on casters and at its lowest height to roll under a former layout that was four feet high. It worked very well. My new layout is in a building purpose built and the layout stands a minimum of four feet off the floor and is designed to not require any ducking under. I am glad I did it this way as I have suffered a traumatic spinal injury and can not get out of my power chair.

    Liked by 1 person

    1. Hi Walt:
      Wow – I had no idea about the injury. I don’t even know what to say – nothing I can think of is really sufficient or useful.
      As for the duck-under, I too am thinking about using a rolling chair as an option for passing under the end of the peninsula. I am confident I could get at least four feet of vertical clearance under the layout at this point – possibly more.

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  3. Trevor, look at what Mark Dance has done with swing gates on his N scale C&W – including indexing, rigidity, and having cars standing on the gates when operated. There is a ton of innovation to glean there. Also don’t discount anchoring to the floor – you could carefully set a few anchors in such a way that the scars in the carpet could be hidden if or when they were removed. Higher-piled capet in particular can be pretty forgiving.

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  4. Outside the box thinking here ( and don’t know if it would even work) but instead of having a duck under or swing gate could you have the two tracks ( & benchwork) act as a keystone and roll on casters or something else on the carpet? You could have latches on the inside to secure it, and then push it out to get outside the layout. Then when not accessing the layout, rotate it 90 degrees and slide it into the aisle way.

    Or have something like that semi permanently attached and those more flexible could duck under and if needed you could open it all the way for those visitors that couldn’t duck under.

    Craig

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    1. Trevor,
      Thanks for keeping us up-to-date on the new layout. I was secretly hoping that you would rebuild Port Rowan, but I understand the scenario you faced and the reasons behind your decision.

      I understand these are just sketches and ideas, but I recall you mentioning during the Port Rowan build, how convenient it was to have the prototype only a few hours away for research vs when you modeled On2 and it was a long ways away.

      Would this new modeling subject have similar constraints of traveling for research? Or do you think you could find enough material via other sources (online, print, etc).

      Craig

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      1. Hi Craig:
        Great question. The advantage here is this is the same railway that I researched for Port Rowan – just a different part of it – so I’m already off to a good start.
        Also, one of the big problems with the Maine On2 layout was almost nobody I knew in Toronto “spoke On2”. Many local modellers had trouble relating to it. That was as much an issue as the distance. That isn’t a problem with the CNR (or CPR) in Canada. Those two railways are common ground to Canadian modellers.
        Cheers!

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  5. You know, it is very likely that you wouldn’t need a duck under for that SP engine terminal…just sayin’…

    A duck under might not be a big problem. Seeing that you have nice carpeting, maybe a just folding bench (crosswise to the ROW and solidly secured to one side of the benchwork) would allow someone to sit & slide under comfortably if a chair won’t roll that well on carpet or is too high to make it for tall operators. I am sure you will come up with an elegant solution.

    I think your plan is positively brilliant!
    The thought of your S-3-a backing down Ferguson Avenue is most intriguing to me.

    Best Wishes

    Liked by 1 person

    1. You are so right. I do hope to do something with the O scale SP equipment. It’s one of the operations dioramas I hope to fit over (or under) the staging areas if I end up building Ferguson Avenue.
      Good thought on the duck-under too. A bench to slide along sounds like a great option!

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  6. My earlier railroads had duck unders and I regretted it every time. No matter how careful everyone is, someone bangs their head or hits the layout hard enough to cause some damage. Getting older also makes it less tolerable too. My current layout has a lift up bridge that was easy to engineer and has worked perfectly so far. I think that designing something for the green access point is both very doable and a much better idea.

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