If you don't already know this, repeat the process of getting the locomotive to derail and see if the wheel lifts toward the outside of the curve or the inside. Also, is it the lead axle that does this first?
I ask this because, as Rich has suspected, when I get a derailment on a curve I always assume the outer rail is lower than the inner, and not all along...it has a measurable dip someplace, and the outer wheel's flange simply slides over the rail and you have your derailment.
I don't see a kink anywhere, and if the tracks are in gauge all the way along, it must be a rail height disparity tranversely...across from each other. I also assume the axles are inserted into their journals properly in the trucks, and that the trucks both pivot left and right the same amount with no snags or binding. If they are all okay, look for a rail height disparity near, not necessarily at, the place where it derails.
All of the comments about checking the power trucks for flat/square, and checking the track for level side to side are very valid. But apparently it is only one engine that repeatedly derails at this spot. I have noticed that recent Atlas engines have been very stingy with the length of the wire that connects the power trucks to the circuit board -- be sure that the trucks have full motion side to side and up and down. I've had to extend some of these wires to make them track better through rough spots.
Ok tomorrow I’ll place a level across the rails, take the shell off and check the wires.
BTW the truck details to the outside rail
Gary
gdelmoro Shouldn’t it be hard to get the paper unde any wheels and not be able to pull it through without the locomotive moving?
Yes......He has that back-wards.....You should Not be able to get the paper under Any wheels. If You can get it under any wheel..that is more than likely Your problem. The slightest dip/high spot in a curve will force the wheel to derail. You should be able to lift the front/rear truck on the bolster on each end at least a 1/4'' up/down....with a twisted truck..it would still derail. There are no shocks/springs on the trucks so there would be one wheel barely touching the top of rail head if a truck was twisted or not enough vertical movement up/down on the bolster.
Or in Your case...In Your photos...I see some almost straight sections in Your curve..not a continuous curve radius and when the engine hits that spot, the back wheel wants to continue going forward and lifts that high wheel off the rail head.....if Your track work is not perfectly level in that spot....even more so. I suspect that like has been explained....You have a restriction of up/down movement in one of Your truks...possibly caused by a short wire to the truck.
Good Luck!
Frank
Once again, it’s not just a simple fix. Today I’ll check the track level and truck movement and get back to youall.
I know the track gauge is good and there are no obstructions (welds or mismatched track connections because I have checked visually, with an NMRA gauge and this track tool slides smoothly arround the entire curve.
I still think that it is the track. When you lay a lengthy curve with flextrack, the individual sections are best soldered together to avoid unnatural segments in the curve. And the flextrack needs to laid on a level, stable surface to avoid waviness. I have seen track work on curves where one rail is higher than the other at one point and then the other rail is higher at another point, sort of like a roller coaster or tilt-a-whirl.
Rich
Alton Junction
richhotrain I still think that it is the track. When you lay a lengthy curve with flextrack, the individual sections are best soldered together to avoid unnatural segments in the curve. And the flextrack needs to laid on a level, stable surface to avoid waviness. I have seen track work on curves where one rail is higher than the other at one point and then the other rail is higher at another point, sort of like a roller coaster or tilt-a-whirl. Rich
Unfortunately for me, YOU are usually correct.
This curve section is about 6’ long and connects to the rest of the curve (another 6 or 7‘). when I installed it I soldered the two sections together on my workbench and then laid it on the roadbed. You may remember this is the section I replaced because it had a bad weld causing derails and was not level rail to rail. I thought it was pretty good but ....
BTW: Those track gauges are for track spacing...not true curve radius gauges...
Take Care!
Right again RICH!
So I placed a level across the tracks at various locations along the curve. At the begining (bottom of original picture) the track is level.
about 1/3 up toward the bridge the outer rail (left looking at the picture) was about 1/16” low. Then it levels out and at the top by the bridge the outer rail was also about 1/16 low. I shimmed the track and low and behold! The loco ran forward, back at step 1 and 14 without any derail. I did this 5 times.
Now i need to permanent affix the track where I pried it out of the ballast to shim it.
Thanks again.
PS: I did writes to HOGTRAINZ where I purchased the locomotive because although the loco no longer derails, those trucks should make contact evenly on the plate glass and they do not.
I don’t know if there is a fix?
gdelmoro Right again RICH! So I placed a level across the tracks at various locations along the curve. At the begining (bottom of original picture) the track is level. about 1/3 up toward the bridge the outer rail (left looking at the picture) was about 1/16” low. Then it levels out and at the top by the bridge the outer rail was also about 1/16 low. I shimmed the track and low and behold! The loco ran forward, back at step 1 and 14 without any derail. I did this 5 times. Now i need to permanent affix the track where I pried it out of the ballast to shim it. Thanks again.
gdelmoro PS: I did writes to HOGTRAINZ where I purchased the locomotive because although the loco no longer derails, those trucks should make contact evenly on the plate glass and they do not. I don’t know if there is a fix?
Even if one or more of the trucks does not completely sit flat on a sheet of glass, as a 4-axle locomotive, the RS-1 should not derail so long as the track is stable and level.
If you just set it on the glass, the trucks may not settle front to back, leaving the outboard wheels slightly raised and all weight on the inboard wheels. You need to see if the trucks easily tilt and swivel, if they do, all is well. Push down a little and it should even out on the glass.
The flange is many times the thickness of a piece of paper. If the paper just barely slips under one end and not under the other - that's NOT the reason it derails.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
richhotrain gdelmoro Right again RICH! So I placed a level across the tracks at various locations along the curve. At the begining (bottom of original picture) the track is level. about 1/3 up toward the bridge the outer rail (left looking at the picture) was about 1/16” low. Then it levels out and at the top by the bridge the outer rail was also about 1/16 low. I shimmed the track and low and behold! The loco ran forward, back at step 1 and 14 without any derail. I did this 5 times. Now i need to permanent affix the track where I pried it out of the ballast to shim it. Thanks again. Gary, the permanent solution would be to remove and re-lay the track on a perfectly level surface. The shims should only be a temporary fix. Then run that loco around the track at least 10 times in each of the four movements that I mentioned earlier to be certain that the problem has been resolved. Rich
Gary, the permanent solution would be to remove and re-lay the track on a perfectly level surface. The shims should only be a temporary fix. Then run that loco around the track at least 10 times in each of the four movements that I mentioned earlier to be certain that the problem has been resolved.
Well, I guess that will be the plan. This time I’ll need to take up the cork roadbed too!