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Tunnel Derailments
Cliff is having derailment problems and needs advice from readers:
“My HO RR has a curve in the tunnel, but it is causing me no end of problems.
The trains run okay from one direction, but derail when running in the opposite direction. Small trains seem to operate ok but the bigger one’s are a real problem. Really annoying. The tunnel is a little hard to access but I have been able to alter the curve a little but the problem is still there. I desperately need help from someone please.”
7 Responses to Tunnel Derailments
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You wrote (Small trains seem to operate ok but the bigger one’s are a real problem). This sound more like a clearance, not a track problem to me. Check using you largest/longest Engine/car you have, and manually push it through the tunnel. Putting a light in the opposite side will help you spot vertical or side contacts made by the Tunnel and car. I had a similar problem. I also used my digital camera to help me spot the contact on video mode. Hope this helps.
If it’s not your track work that is causing the problems, then it may be a clearance issue. Some cars or Locomotives extend way out over the curve radius, and may be hitting the inside of your tunnel. As for the track, make sure there are no kinks where there are rail joiners, and that the track is level.
If the curve radius is too tight, that can cause too much tension between some cars and locomotives, especially longer cars and locos.
If you are using flex track in the tunnel that is a good thing. But if there is a rail connector in the curve flex track tends to always try to go straight at the joints even if it is nailed or glued down. If this is so at the joint the rails will jog going through the joint. To Remove that jog in the rail Pull the flex track up and and allow the rail to straighten up. Gently soldier the connector with the rail straight from the outside of the rail. Then flex the flex track back into position and you will find the rail continues the curve evenly as if it is one piece. from Newman
I have had this problem several times, My worst problem was a sharp curve on an incline it was around 20″ radius and 00 code 100 peco steel flexi track, the problem was the track kept wanting to straighten out causing kinks at the rail joiners no mater how many pins or even screws I used and by straightening it made the radius uneven, The cure was to 1) ban long wheelbase 4 wheel vans and 2) relay in Hornby code 100 steel 3rd radius set track, I really needed 4th radius so I eased the curves out by cutting the webs between sleepers and easing the curve to be less sharp, cutting and filing the rail ends to be parallel.
Another problem again with 00 is the track not remaining flat, so cars drop slightly as they pass except when part of a long consist the couplers keep them in line and so they derail by being lifted.
And last I had an outside reverse loop and trains would run round one way but not the other, like run round clockwise with A end leading but derail with B end leading, it was primarily back to back problems with the wheels but the Hornby stock I used had moulded plastic axles and you couldn’t adjust the back to back, I simply abandoned the loop, I just could not fix it.
Yes all that comes into play with flex track. Like I was telling Cliff, Fit the track then straighten the rail through both pieces of flex then solder the joint to the rail. Then flex both pieces as one and your joint will hold the rail in line with each other as one track. Also spread APEX Caulk onto the roadbed and lay the track on it. Be sure to evenly weigh it down along its path and it will hold as you put it. It should set say 30 minutes before removing weights. If for any reason you should need to pull the track up just slide a thin bladed putty knife under and along the track and it will come up without damaging the track. I no longer use track nails as this is much better Called DAP APEX PLUS and get the clear and you will not know it is there after it dries. Menards is a source that is inexpensive. from Newman
When building tunnels or hidden places the trains will travel allow yourself an access point or cover to get in there and do maintenance. I usually will build a lift off of the scenery or hill so I can easily get to all the track in that tunnel. A cleaning rod will work depending how far you have to reach in but fixing problems or getting a derailment out usually requires better access. For a lift off of the scenery I mount drawer pull handles with flip down handles. I mount them to the part I will lift off. Once it is back in place I usually lower the handles flat then place a stack of stone usually made out of layers of ceiling tile (the fiber type.) No one will know the handles are there. Even use a building to cover the lift handles. A lift off is something that you will be glad you did. When done right you would never know the lift off is even there.
from Newman Atkinson
A rail joint when viewed from above is sometimes not straight so that the flange of your wheel catches on the rail at the joint in one direction but not the other direction. Soldering the joint or just bending the offending piece of rail with pliers to straighten it will normally fix the problem.