drop bridge for a walk through ?

Question

Any one have suggestions on how to make guides for a lift bridge so it will settle in the exact same spot every time ? I have built a walk through bridge for my layout. Its 30" long and 30" wide with flush mounted hinges. I also need ideas on ways to hook up connections so that when the bridge is up the trains will stop short of the opening to prevent a train accident equivalent of the running into the grand canyon. thanks for any help in advance. Eddie

Bob May · Accepted Answer

You need to use some good tight hinges at the hinged end and put a pair of pins for the flopping end of the bridge. I've also seen V blocks of steel or aluminum used to get the horizontal alignment right with the blocks bein adjustable for the vertical alignment. A latch will keep the bridge down unless you want it up. The spring type is the best as this will keep the bridge locked down positively to the stops.

-- Why isn't there an Ozone Hole at the NORTH Pole?

E. T. Atkins · Answer

thanks Bob :)Bob May wrote:

William Pearce · Answer

To stop a re-run in model form of the Central of Peru's Chaupichacabridge disaster, install a micro switch on the abutment at the non hingeend, and wire this to track sections of suitable length on each side of thebridge. When the bridge is up, these sections will be dead. Perhaps even asmall push button on-off switch could be used.                        Regards,                                            Bill.

Jim Stewart · Answer

How about just placing a wedge barrier on the track before opening the bridge?Jim Stewart

Craig Douglas · Answer

When we had ours we used two of the sliding bolts you might find added to a house door ( the smallest we could find) to lock the bridge in the correct place.

For our electrical connectivity, we used 25-way connectors between the two, but we made no provision for trains running off (and surely enough, one did).

I'd imagine the best way would be with the push button switches as someone else described with isolating sections. To ensure it's automatic though, I'd put the have the bridge rest on the swiches whilst down, that way the cut-off is automatic. Switches attaches upside-down to the underside of the drawbridge would control the isolating section on the hinge side, and swiches attached to the base where the bridge rests would be the correct way up and control the isolating sections on the gap-side .

(Obviously the weight of the bridge shouldn't be entirely supported by the switches or they'll wear out quickly)

Hope this helps..

Craig

harrym · Answer

There is a piece of cabinet hardware called a bullet catch.  It is used to hold doors shut.  They are installed by drilling a hole in the frame and pushing them in.  They have a spring loaded "bullet" to put pressure on the door.  If you isolated a section on each side of the bridge and wired the feed wires to the bridge, you could fashion a switch with the bullet catches to pass the electricity to the isolated sections.Craig Douglas wrote:

Wolf Kirchmeir · Answer

"A Drop Bridge for the MR&T", by Gordon Odegaard, Model Railroader July

1990, pp. 78-81.

It may be available on MR's website (I haven't checked). If you send me your snailmail address, I'll mail you a photocopy. Drop the first (or second) 'w' in the fromaddress.

HTH

E. T. Atkins · Answer

Thanks for all your help yall :)I will using your suggestions :)"E. T. Atk

Randy Sweeney · Answer

how about steel or brass pins and plastic funnels at the corners for alignment and adding a microswitch that cuts power to the adjacent track segments when the bridge is not seated properly

drop bridge for a walk through ?

Join the Discussion

Didn't find your answer?