Lionel/MTH 042 Switch problem (derailing)

Since no one else has jumped in here, I'll give it a try.  There are a lot of factors that can be part of the problem so proceed cautiously with modifications.  Yes, tinplate switches can require a little finesse to get working correctly sometimes.  You may notice that the frog point that the wheel trips on has a small screw head in it; loosening this screw just a partial turn can let you ooch the point one way or another, re-tighten, and that can help.

As often as not, I find the issue can be with the wheel set, not the switch:  a set of wheels in which the wheels are mounted a little too far apart from each other on the axle (too wide a gauge) can cause this.  So you might see if this dersilment happens with all wheels on this switch, or with just this one set of wheels.

Wheels and switches can act very differently under power than when pushed along, so I wouldn't jump to too many conclusions until you at least try a train under power across the switch.  Also, the approach coming into a switch can be a factor; if the train is coming out of a curve into the switch it will act differently than on a straight. If there is any unevenness in the layout surface, this can also cause problems.  

Tinplate is made with very loose tolerances; it's supposed to be that way.  Also, it's made out of tin, so sometimes things can get bent out of shape in shipping, etc.  If a truck is tweaked, the wheels will be out of alignment.  These can be carefully bent back to where they should be.  

In my experience, most of these out-of-the-box issues can be resolved by just the right amount of careful tweaking (bending just slightly) in the right direction in the right place. I'd try everything else before putting a grinder to it.

Shim the guard rail opposite the frog so it is pushing the wheelsets closer to the outside diverging rail and away from the frog... as close as needed but not enough to pinch the wheel flange.

mikemike,

    I look at this completely different than Rob, these Lionel switches were not designed to accommodate Tin Plate and I have no intention of reworking every switch I purchase.

I am being told the new 048 & 072 FasTrack Command Control switches will accommodate most all Tin Plate engines and rolling stock, no modification required.

I have yet to test them out, but I am going to on my next layout.  I do know the old 072 & 711 switches accommodate all my Tin Plate, I ran all my different O gauge trains with them engineered into my FasTrack layout, it worked great.  The 036/042 FasTrack swithces you have I returned because they did not constantly accommodate my Tin Plate originals or MTH Repros.  I expect the NIB switches I purchase to run perfectly with the Tin Plate Engines and rolling stock I own, no rework required.

If you intend to run Tin Plate trains my recommendation is to get rid of those 036/042 FasTrack switches.  The RealTrax switches are even worse.

PCRR/Dave 

The engineering that right now I know works all the time, every time, with all my Tin Plate Trains and my modern trains also.

Thanks for the replys.  Sorry, I forgot to mention the switch type.  The switches I have are the current production Lionel Standard gauge switches in 042.  They are not the fast track switches. 

I have tried moving the frog point and it didn't help. There is one straight section before the turnout.  I suspected the wheels but when I looked at them they were all very loose and the wheels have a serious amount of side to side movement as well as truck movement.  So I am not sure where the problem lies? I need to power up and try that. 

mikeman,  my MTH switches I have the right and left turnout.  When my # 10 or my # 384 run through them they both make a noticeable bump noise but no derailment.  I have never tweaked them but I do not screw them down to the Christmas layout .  I screw the straight before and the straight after the switch.  My # 38 with the slider shoe has to run through at speed or she will die on the frog at slow speeds.  The train engine is the only one that makes like a car hitting a pot hole thump.  The # 384 is new mth and the # 10 is vintage tin with new wheels .  

The problem is that the guard rails opposite the frog are not pulling the wheelsets far enough away from the frog, and the flanges are picking the frog.

Shim the guard rail opposite the frog so it is pushing the wheelsets closer to the outside diverging rail and away from the frog... as close as needed but not enough to pinch the wheel flange.

YOUR RIGHT! It only derails about a third of the time when I pull through with the coupler. 

You know that was my first thought also because when you take a straight edge it looks like that is whats needed. one mm maybe less. If one does end up having to do this do you glue a piece of some type of plastic or what?

Why not replace the guard rail with the larger one.

lucky,the only engine I have that hates it my 380,,yes very loud bump but never derails

Didn't know you could do that

Using the above solution as a guide, you can simply extend the guard beyond the rather short ones on these switches with cut/shaped styrene affixed to the originals.

Gentlemen,

    Whether it's STD or O gauge I can not believe you gentlemen are willing to rework every brand new switch you purchase.  Not for the cost of these new switches that is for sure.

PCRR/Dave

So... are we are using the guard rail to keep the axle perpendicular to the outside rail? That makes sense to me.

The wheel gauge is another matter on standard gauge since the wheels are free floating on the axles, right?

I do not know. He says they are removable. Then why not buy the newly sized part and replace the old one. Should work.

The large gear of the super motor is hitting. Not much you can do about that.

sort of.  There's a crimp on the axle inside the wheels, and the truck outside the wheels.  Depending on how the side of the truck is bent, it can narrow the gauge or restrict the wheels.  Also, I have come across plenty of axles that are crimped in the wrong place, forcing the wheels to a wider gauge.  You wouldn't think that would happen, but it does.  Tinplate.

However, if the crimps are too close to the center of the axle (a more common problem) washers can be slid on between the crimp and the wheel, a lot of gauge issues are solved this way.

Bobby, thank you for that excellent diagram, this has been talked about before but the graphic really helps.

Large gear super motor, different problem from the derailing.  What was the deal back in the day?  We complain about MTH not doing its homework and making the Super 381 so it has difficulties with stock track, switches, lock-ons... but Lionel made locos that wouldn't go thru its own switches?  Same with the trolleys... and unfortunately Lionel Classics repros of the trolleys too.  The large gear super motor can be swapped out for a small gear super motor, but the trolleys can't.  

Thinking of making an elevated loop with no switches to run some of these on. Meanwhile, run McCoy trolleys.

MTH tech support says they do not have the larger rails for the standard gauge switches.