I am currently re-laying the curves on my fathers layout to run a BLI 2-10-2. I upgraded them from 20- 21 inch to 22 inch minimum. That is the largest curve I can put in the space available. I have redone 3 curves and the engine runs great on them. My fourth curve has an Atlas 30 degree crossover in the middle of it. The locomotive goes through the crossover and when it gets to the frog it derails. the front drivers are raising up and then going over the side. I checked the alignment and it looks good. All track is HO Atlas Flex that has staggared joiners and are soldered in the curves. The crossover is not soldered. Any insight into this or what to check for would be helpful?
My guess is that it is derailing to the outside of the frog. The locomotive is probably pressing really hard on the outside of the curve rail. While the crossing itself is straight it is not straight for a long enough distance. The rear drivers are still in the curve pressing the front to the outside, so it dives into the gap. The solution would be to put a straight section long enough for the locomotive to be going straight when it hits the frog. I am also guessing that there won’t be enough room to fit this in.
Perhaps the curve could be spiralled in tighter than 22" in order to fit the straight section?
Thank you for the heads up on this. I will try and incorporate a straight section there or at least ease the curve before it. This has been a very tricky part of the layout, but I am determined to get it to work
Atlas turnouts and crossovers sometimes are too high in the frog area. Hold a ruler on edge over the frog and see if the ends can be rocked up and down. If they can, you need to file down the frog to make it level with the rest of the track.
Also check to see if the wheels are derailing on the tip of the frog. If they are, you may need to narrow the gap between the guard rail and outer rail to pull the wheels away from the frog. On some turnouts and crossovers, I have been able to do this with a pair of pliers by exerting enough pressure on the plastic guard rail to bend it closer to the outside rail.
I have two Atlas code 83 crossovers in the middle of curves on my HO layout, and don’t have this problem with them.
Check the flangeways with your NMRA gauge (if you have one). I found the flangeways were in gauge on one side of the crossing but too tight on the perpendicular side.
Which wheels? If it is the pilot you may just need some more tension on iy to track. Drivers, that is a probelm with a 2-10-2 the length of lead into the 30 should be at least the length of the drivers this should stop the drivers from climbing the rails. The code 100 is not as bad as code 83.
Well I replaced the cross over with a new one and also widened the curve a little before and after the crossover. The locomotive now goes over the crossover without derailing, but it lifts up like it is going over a bump. I will have to try the ruler check to see if the frog is to high in the middle. I appreciate all the ideas, I have checked the wheels on the locomotive with an NMRA gauge and they are all ok. I will check the flange ways to see if they need some correction.
Someone reported that Atlas turnouts are out-of-spec with regards to the guard rail spacing opposite the frogs. There’s too much room between the stock rail and the guard rail. Most of the time, this is just a cosmetic issue, but it does allow wheels to climb up on the frogs more than they should. This may be an issue with crossovers, too.
You can get a very thin styrene strip and glue it to the guard rail, so that the gap between the guard rail and the stock rail is smaller, and the wheels are forced to stay closer to the stock rail. You might want to try this first with tacky glue so you can remove it if it causes other problems. You could also try a thin strip of sheet metal or copper for this.
