# Front Trucks of Steam Locos Derail -- Help?



## MtRR75 (Nov 27, 2013)

First a little background. I am relatively new to model railroading, but have been reading up a lot in the last couple of years. I inherited a 4’ x 8’ HO layout – just the table and the track – no structures or rolling stock. The wiring was done with undersized wires and I did not like the arrangement of the control panel, so I have completely rewired the layout and have almost completed the new control panel. The track appears to be Atlas code 100 track with Atlas Snap switches, but it is all brass – not nickel-silver. Curves are 18” radii. Most of the track is soldered together, except for insulating junctions. I am running a DC system.

So now I am testing the track with several of the steam locomotives that I have accumulated in the meantime. (The plan is to model 1920s steam.)

I have a Bachman Spectrum 2-8-0 and an IHC 4-6-2. The problem is that at certain places in the layout, the front trucks of the locos derail. This always happens when crossing a turnout and usually only at one turnouts and only in one direction. I have watched these derailments many times in slow motion, and have even hand-pushed the locos very slowly through the turnouts to see what is going on.

Each locos derails in a different location.

The IHC 4-6-2 derails when in enters the points end of a certain turnout that is set to route the loco to the curved end of that turnout. The loco is coming off of a curve, as it enters the turnout, but the curve is in the same direction as the curved portion of the turnout (no S curve). The front truck wheel on the outside curve appears to slice in between the end of the point and the straight stock rail – instead of staying on the point. If I remove the load of cars and run the loco/tender alone, it almost never derails. The pull of the cars (just 7) seems to pull the rear of the loco towards the inside of the curve and thus push the front of the loco towards the outside of the curve, enabling the front truck wheel to wedge in between the point and the stock rail.

There is plenty of play in the front truck, so that is not the problem. There are several similar situations elsewhere in the layout where the loco does not derail. I have felt the end of the point with my finger and it appears to be about as flush with the stock rail as the other turnouts on the layout. The Spectrum 2-8-0 does not derail at this location, but it does shift around more than it should and does not run smoothly through the turnout.

The Spectrum 2-8-0 derails at a different turnout, when entering from the frog end on the curved side. Here the front truck derails just as it is leaving the ends of the points. I can’t see why this happens. The outside wheel seems to drop off of the point onto the ties just where the point comes up against the straight stock rail. At the same time, the inside wheel climbs over the curved stock rail to the inside. I can’t tell which wheel is the initial cause. There is nothing in the trackbed that would force the inside wheel up – no ballast at all. This problem occurs both with and without a load of cars. I wonder if the weight of the drive wheels on the point pushed it down a little, possibly causing the truck wheel to derail – but that is pure spectuation.

There are several similar situations elsewhere in the layout where this loco does not derail. If the loco enters this turnout on the straight side of the frog end, it does not derail. The ICH 4-6-2 does not derail at this location, and runs pretty smoothly through it.

Although these are different problems, they have a lot in common. Has anybody else had problems with front trucks of steam locos derailing in turnouts?


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## D&J Railroad (Oct 4, 2013)

The first thing I would do is check the guage of the wheels on the front truck. Also, check to see if the wheels are free wheeling. If they bind at all, that will cause them to want to climb the rails on curves or turnouts.
I would also check the points of the turnout. They may be snug against the stock rail, but if they are not at the same height as the stock rail, that will cause derailment as well.
For track where the wheels derail, you might check the trueness of the track. Use a flat piece of wood, i.e. edge of a 2x4 or small piece of plywood and lay it on the track then slide it along and watch for drops or rises in one rail or the other. Excessive flex in the track will cause derailments as the truck isn't able to tilt enough to keep both wheels on the rails.


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## 93firebird (Dec 25, 2011)

My Bachmann 2-10-2 had a similar issue when going over switches. I fixed this by taking a spring from a "clicker" pen and cutting it down to length. The loco has a hole for the screw that holds the shell to the frame. this spring fits snugly in the hole and applies a downward pressure on the leading wheels.


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## DonR (Oct 18, 2012)

All of the suggested possibilities are right on.

But I would also be very suspicious of those
Atlas snap switches. I had a number of new
nickle silver Atlas turnouts and finally pulled 'em out and
replaced them with Peco Insulfrog and there was
no more derailing.

The Atlas points often do not accurately fit into
the rail niche or sometimes the points are lower
than the associated rail. Either of those faults
would cause your derailing. You can do some
fiddling around and overcome the problem. 
I just ran out of patience.

One word of caution. Pecos do not use the same
track lengths as Atlas turnouts thus are not
direct replacements in existing layouts. Adjoining 
tracks would require changes. 

Don


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## ggnlars (Aug 6, 2013)

If the loco's are derailing at the same place each time, even though it is different for each loco, then there is a problem with the track at that location. If they derailed at different places then it is likely the loco design. Older models were designed to run on 18 in radius curves and #4 turnouts. The same type loco designed for today's modelers probably will not. A convenient tool is Micro mark's track inspection car. It is basically a blear piece of plastic with trucks. It allows you to see and feel the condition of trouble spots in the track. These loco's have identified something. To know how to fix it, this tool and a NMRA track gage will help you figure that out. 
Larry


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## blackz28 (Jan 6, 2013)

when i had a front truck derail on my steam locos i did the washer trick for weight , that always seem to do the trick


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## MtRR75 (Nov 27, 2013)

Thanks for all the ideas. It will take some time to try some of these. Been kind of busy with the holidays. I'll get back to you after I get a chance to experiment some more.


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