Model Railway Forum

Three bridges in fact measuring in total 1350mm made up of 600mm bowstring, 150mm girder and 600mm bowstring, as seen here

The bridges go diagonally across the middle of my layout and I can see that I could give rise to a number of problems.

Power - I think that I should be able to use only two pieces of flexitrack to cross the span with the droppers soldered on at each end with the wires hidden in the abutments.

Track - This is where I start double guessing myself. I need to make sure that the track is flat and stable, I can stick a cork track bed to the bridges but how do I keep the track in place on it, glue that as well?

As the bridges are diagonally across the middle Murphy's Law says that as soon as I've fixed it down I will find it is in the way of something that would be so much easier to do if I could just remove it for a bit.

Am I just being paranoid?

I think if I were undertaking the bridges I would pre-assemble the track, solder the metal fishplates to all rails only on the bridge sections, but not beyond the bridges ends, then thread the track in place. No droppers are then needed on the bridges and you're sure via the soldered joiners of good electrical connections. Add rail feeds to each end and ensure a small gap is left between abutting rails for expansion at each end, 1.0mm should be sufficient if the track is laid in ambient temperature of around 20°C.
Dont use underlay on the bridges decking, apply glue to the sleepers before threading track in and then gently press down on the track to ensure its level. I would use a contact adhesive applied to about every fourth or fifth sleepers undersides.

You will probably need a second person to help with the threading of the track depending on how long the actual span is.

I hadn't thought about soldering the rails together to have a single piece of track going across. Thanks.

How about bolting the track to the bridge.

I have not donethis myself but you can get tiny track self tapping screws with very smal heads. Only an idea. As I said not used them personally................. John

Whichever way you do it, it's going to look pretty darn amazing. R-

Hmmm .... generally the message is don't stick it down, will look at the options suggested. Thanks, off to find my Man Tin.

RogerB wrote: ↑Tue Nov 13, 2018 3:46 pm Whichever way you do it, it's going to look pretty darn amazing. R-

Thank you (blush)

Solder thin tinned copper braid to either side of the fish plates to still allow expansion.....

A thin bead on "No Nails" grey colour will hold the sleepers in place, down the center then hid it with ballast....

Good idea Ray, never seen that done before.