I’m getting close to the point of needing the bridge across the doorway into the train room. Originally I had planned to use a swing gate for this purpose. Indeed, the track plan still indicates this as the intention. However, I decided quite some time ago that a swing gate wouldn’t be ideal in this particular installation (read about that here). If you took time to read the original post, then skip the next couple paragraphs, otherwise let me explain further.
One of the key scenic features that I’ve planned for the layout is a long, low trestle crossing a semi-swampy waterway…something quite common in south Louisiana. In the early days of fiddling with the track plan, I decided that the only proper place for this would be near the town of Monterey, the western terminus of the railroad. Monterey is located near the Mississippi River in a low-lying area just south of the Angola State Penitentiary. As such, I decided that the minimum benchwork width for this needed to be 12″ so that at least a semblance of a waterway could be modeled. The final location of this area ended up right in front of the entrance into the train room.
A (swing) lift-up wouldn’t work here as the benchwork is angled across the entry, and when swinging the section up, it would crash into the lighting valence already in place. Hence, the swing gate was decided on. But there are problems with that. When I started studying the needed design in detail, it became apparent that it wouldn’t be practical to build something that, when open, would rest up tight to the benchwork, allowing a reasonable passage in the aisle way. The combination of the 12″ width and the required hinge location point make this infeasible (look at the track plan on the website to see what I’m talking about).
So next, I decided that a swing down bridge might work. Some preliminary drawings I sketched show something that would probably work pretty well. The plan is to hinge it from a point several inches behind the joint, and have the bridge section swing down into a “box”. This box would protect the section while down. I likely could even come up with something to make it easier to lift such as one of those gas pressurized struts similar to those commonly used in the automotive industry.
This is my most likely candidate.
One other concept I’m revisiting is a lift-up section that would have the entire bridging section lift rather than swing (a vertical lift bridge). I would use telescoping drawer slides at each end for this to work. I think the actual bridge design and construction would be rather simple. I was originally concerned about overhead clearance, but that may not be an issue after all. However I’m concerned about the final weight of the section. I suspect that some sort of counterweight system would have to be employed so that the bridge would raise easily, preferably using a single hand. That makes the design considerably more complicated, though not insurmountable.
I am doing further research on that concept presently.
Once I have a decision, I’ll probably get started with the bridge. The benchwork at Monterey is well along, but it will be pointless to spend energy and time putting in track until the bridge is in place, as you can’t leave town without it.
Write if you have ideas or comments.
-Jack
