I am working on laying out a small HO scale layout using XTrkCAD. The problem at hand is inserting a Micro Engineering 50’ through girder bridge into a 90 degree 27" radius curve, some where around mid curve…while maintaining the ability to handle IHC heavyweights…in the least possible space.
What combination of straight sections and/or easements on either side of the bridge will give me the necessary clearance for the heavyweights? The layout work I’ve done so far has been with XTrkCAD’s easement setting on “Normal”. At this setting, with an additional inch of straight on either side of the bridge, I’ve come closer than comfort to the edge of the benchwork…and I do not know if that combination is even enough.
All kinds of questions come to mind. With inserting 7+" of bridge, are the easements necessary? Would the “Sharp” setting produce easements condusive to the heavyweights? How much straight track is needed to keep the cars from clipping the girders?
Any insight that can be offered will be greatly appreciated.
This is certainly abit of a minefield of a question but il try and offer some advice for you.
Firstly i dont have any experiance of using XtrkCad but i have used another layout design program in the past. The problem you have is also very diffcult to ‘see’ from across the internet but-
If it were me i’d layout some flexi on a work surface and look at the clearance’s and room involved that this sittuation will take up. Bear in mind that any easement to or from straight is going to take up valuable space.
In answer to the question are easements necessary? I would say that if a straight is inserted to negotiate the bridge, yes certainly unfortunately!
On my old layout i had a short straight section between 2 curves and trains didnt look very good traversing this section, lurching from one curve to the other, not good. I certainly would’nt do it again.
Are you sure that the curve could not be continued through the bridge? How long in scale feet is an IHC heavyweight?
I guess if over about 75 feet probebly not as it will hit the bridge.
Qoute-How much straight track is needed to keep the cars from clipping the girders?
Probebly atleast a car lenght each side of the bridge.
Sorry i havnt been very much help but atleast it’l get it back to the top![:)]
Zandoz, an interesting problem. I tried what you are describing in XtrkCad and do not believe it can be done and still maintain a decent radius - even with easements turned off I could only manage a 17" radius from the straight to the 7" straight piece representing the bridge. I would suggest kit bashing a plate girder bridge instead to fit around the curve.
I agree with Gary’s idea as I feel that it’s your only option,being limited in available space as you say you are.Setting up a temporary trackage to test the actual dimensions involved is by far the first thing to do as your drawing software,no matter how accurate it may be,could be misleading you.
I wouldn’t create easements for this situation but would rather have the curve constant through the bridge,like Gary said.This way you would cure your space problem and,just as important,you wouldn’t have a break in your curve.
And if tests reveal that cars do hit the girder,you could widen your bridge a little by splitting it in halves and adding a piece of scrap plastic in the middle.When glued back together,your trackwork would likely hide this modification.
If I were confronted with this situation and were still only in the design phase of a layout, I would consider moving whatever terrain feature the bridge is going to span to a section where there is only straight track.
Most certainly, yes. Now is the time to play You-Know-Who and to manipulate the really concrete stuff over and around which your trackage will have to negotiate. By moving mountains and streams now, you can manipulate your lines back further on each side of the obstacle and get them to meet mid-deck on a nice bridge that is where it ought to be.
Thanks for your input, folks. This whole project (if it gets beyond planning) is going to be an exercise in long-term extreme compromise. Health/mobility issues combined with moisture issues have ruled out the basement layout I’ve always wanted (and started but forced to abandon). Lack of dedicated layout space in the rest of the house, the need to be able to store what ever is built, limited working space, and the very possible future need for wheelchair access, have combined to dictate construction based on shelf size modules or nothing at all. Fixed income (see health/mobility issues) mean absolute minimum budget…and making use of what I have.
What I have is several large storage tubs of buildings, sectional track, turnouts, locomotives, rolling stock, bridges, etc. (all never been used, most still in original packaging)…a tool inventory that would make Tim Taylor the tool man drool…and 30 years of system analysis, design and implementation experience on everything from go-carts to homes and computer systems.
Where I am right now is trying to see if I can come up with a rough plan that will justify actual experimentation. As things stand now, 72"x16" modules, assembled into a 72"x104" squared-donut with one peninsula module, is my manageable limit real estate wise. My life long fascination with passenger trains, and close to a dozen IHC heavyweights somewhere in those tubs dictate a minimum of 27" radius turns…the shallow shelves not much room to play with their placement. The ME bridge mid curve? There is one somewhere in those tubs, and one of the plans I’m playing with, has unallocated curve space to possibly put it.
If you use the ME open deck bridge, instead, you can carry the curve over the bridge.
Would the scenery plan accomadate an even longer bridge? If so, you could alter the ME steel viaduct, but use only the 30 ft sections so tie/ track overhangs won’t be as noticable as on the 50’.
ME has a code 83 bridge flex track that can tie into the remaining mainline track just past the abutments.
Straightening out a well laid curve to accomadate a 50’ straight could create many other headaches as well.
Have you considered flipping the bridge upside down to create a deck bridge. This would leave nothing sticking up for the heavyweight cars to hit and eliminate the need fro easements.
The reason for the thru-girder bridge is the same as for their use in many prototypical situations…clearance under. The street under would need a little “Low-riders Only” sign…LOL. But this did give me another idea to play w