Help troubleshoot derailments on hinged bridge.

The best way to find the problem is to observe wheels from each side as engine creeps along.

Split may be enough to give you problems. 

I put some small slide bolts to maintain the alignment. 

One outer rail on each side has nothing connected to it. The rail is probably shifting and going out of gauge causing your derailments.

I think you need pins.   Consider putting the pins in the stationary section.  On the movable section cut back the ties a little and spread open the bottom of the rail.  When the movable section comes down the rails go over the pins and  improve alignment.

YMMV

Bill

The Ross ties are not oriented to maintain good alignment at your bridge angle and as you have noted, easily split.  Fashion double width ties from pine or plywood and lay them under the rails parallel and flush to the seam.  Then spike the rails into the pine ties - its more secure than basswood ties.  If the spikes work loose, replace them with track screws.   If you don't have registration pins or other means to ensure alignment of the roadbed, work on that too.

When I did my liftout section and the track curves at both ends I had trouble with the rails not lining up good. So I added these from Gar Graves. This worked for me to keep the rails lined up.  But they may not work with the Ross track because the raik sits on top of the ties whereas Gargraves is open through the ties. Maybe if you could substitute with Gar Graves in that area cutting through the Gar Graves and then connecting that section to the Ross ... Paul 2

#910-4 Connectors

While troubleshooting:

1. Is it weight that is causing the derailement. Perhaps weight on the bridge is causing the rails to not match as the locomotive approaches the joint.

2. Does the derailment happen in one direction or both directions of train travel.

3. Does the derailment happen either or both freight (shorter) or passenger (longer cars). 

4. It looks to me that the flange could pick the outside rail of the bottom track on the third picture.

I agree with all previous comments, the outside rails on the bridge must align with the stationary outside rails on the approach and egress from the bridge. I have three opening bridges and misalignment will cause wheel flange climb and derailment. Also check how stationary the bridge is left to right on the non-hinge end, you may have to apply side retainers on the non-hinge end, these restraints will should be set to allow clearance for opening the bridge vertically and still minimize transverse motion of the bridge and outside rails for misalignment with the stationary rails. I applied side retainers to all three lift bridges, make sure that there are no burrs on the cut ends.

IMO your issue is the drywall screws you’re using. They are tapered and they stick up way to much, also they’re huge. Use the screws Ross switches sells. Also the rails must be loose , hot glue your rails on the outside. 

Alex 

After you get the rails lined up perfectly and fastened down securely, lay a popsicle stick or flat ruler across the rails. Slide it back and forth. File the joints until it's smooth with no bumping. The gaps shouldn't be big enough to allow wheels to dip. So don't over file them.

@Alex M posted:

IMO your issue is the drywall screws you’re using. They are tapered and they stick up way to much, also they’re huge. Use the screws Ross switches sells. Also the rails must be loose , hot glue your rails on the outside. 

Alex 

No offense intended, but why use such huge, butt ugly screws on a nice layout???

If you switch out those screws, use #4 panhead in whatever length necessary to secure the track; e.g., 3/4" or so.

Also, the bridge needs to laterally and vertically secured--what are you using to accomplish this???

@Alex M posted:

IMO your issue is the drywall screws you’re using. They are tapered and they stick up way to much, also they’re huge.

I absolutely agree. Those screws are way too big!

I also think your rail gaps are too big. In your bottom picture, I can see how a flange on a wheel of a train moving south (down) could easily pick that angled gap on the right-hand (outside) rail.

Atlas O track screws work well with gargraves too.....

My movable joints (geezer gate modules and turntable) have all been square to the track - not angled as your bridge.  Trains run through fine even though the rail gap ranges from 1/32 to 3/32 and alignment is not perfect - particularly on the geezer gates which get a lot of use (and abuse) on active layouts at shows.  A slight horizontal misalignment on the square gap is tolerated by 3-rail flanges but vertical misalignment is not.  

The angled cut of your bridge lends itself to a sharp point on the outside rail that wheels can pick.  The first thing I would try is filing the points of the rails to hopefully keep the wheels from grabbing it.  I bevel the inside edges of my square gap rails.  Ensure the tops of the rails are even and level when the bridge is closed.  Stabilize the rails from shifting as heavy scale equipment runs across it - previous posts offer suggestions and I'll add Steel Putty epoxy as another fix.  You might try guard rails (as used opposite switch frogs).  I have built diamonds for curved crossovers which have 1/8" or bigger gaps for the crossing tracks - and with guard rails integrated with the design, they work perfectly.

If you cannot get reliable operation on the angled cut, then I recommend you re-engineer the bridge for a square cut on the rail ends.  Making a one-way diamond to cover the bridge joint is a possibility.  The rails can butt squarely to the diamond and  the angled cut goes through the diamond.

If you have a straight lift out or hinged bridge, you can have straight cuts.

If you have a swing out gate, you must have angled cuts.

"If you have a swing out gate, you must have angled cuts."

Agreed.  The OP's blurry photo seems to indicate a upward hinged bridge.  If the rail alignment tweaks don't work, then a rework for a squared cut on the track is what I would do.

 The rails will have a little wiggle room in ties. I believe the hinges themselves probably  contribute more to the problem. The further the span. The more it will show. In your first picture. It looks like the bridge Is just resting on a block. Get the track lined up. Then use wood or metal to keep the bridge itself in line with the benchwork. 

 Follow the suggestions above. Alex, Tom, John and Paul offer good suggestions for keeping the track in line. Paul mentioned the Gargraves rail joiners. These are handy to align the rails if you remove or add  trackage such as a turnout and can no longer insert pins without ripping everything up. I believe these are stainless. I’ve used brass strips and soldered them to the rails. When you drop the bridge. These can slide inside the rails.

Hello David,

In your original posting you didn't state from which direction the derailments are happening.  Are they much more prevalent in one direction vs. another.  If so then look at the points as others have stated. 

The outside rail looks like an issue to me especially if the train is coming from the top of the picture to the bottom.

As others have stated, reduce the size and height of the screws being used as it looks like they are sitting much to high and could be snagging a wheel set when it comes through. 

Take one of the engines that derails and very slowly freewheel it across the bridge.  While doing so carefully examine how the wheels (especially the front trucks) are moving.  If you feel any resistance even for a moment.  Back up the engine and try that spot again.  Should it happen again, look to see what is going on as this may be your issue.

You need to do some detective work in order to figure it out.  Also note what happens to the bridge height as the Locomotive crosses onto the bridge.  Does it sag or shift.  If so shore up the bridge so that it cannot move.  

These are my initial thoughts just looking at two good photos out of three.  A short vid would help as well in the diagnosis for us who are trying to assist from a distance.

David,

Just wondering how this one turned out- what was the issue? 

thanks

Smaller screws as mentioned.   #4 x 1" or Atlas track screws which are #2 X 1"   An assortment of screws pictured. Track ties should be pre-drilled.

Hinged bridge can be a problem.  Note the added piece to correct a too short lead-in rail .  The small rail pieces were soldered in place to the end of a Gargraves switch.

Sorry for the poor picture.

One area or rail might cause problem. Inside rail has sharp edge,if train is going away from bottom of pic, the flange could pick the sharp edge. We have gaps in our club portable modular layout some 1/4"  seems to work. Pins would be better,but setup time is more important.