Front bogie lifting on curves and/or leading wheel not rotating

[Gremlin]

Hi All

 

I have a collection of new model (as in DCC era) A1, A3, A4 and B1 locomotives that I am running on a test oval (double track) on a marble bench top.  I am using Fleischmann N scale track and it is flat on the table top.  The curve radii are 43cm for the outer and for the inner, 39.6cm.

 

On the inner track, when going around the curves, all locomotives that are 4-6-2 or 4-x-x, either lift the bogie slightly or, if the bogie stays flat, the leading wheel doesn't rotate.  I would have thought that an almost 40cm radius curve would have been enough for accurate running...so any suggestions?

 

Thoughts (but not yet tried) include placing some weight on the bogie or super elevating the curves...any other/better suggestions?

[mjkerr]

The curve radii are inner, 39.6cm.

 

On the inner track, when going around the curves, all locomotives that are 4-6-2 or 4-x-x, either lift the bogie slightly or, if the bogie stays flat, the leading wheel doesn't rotate

Sadly this suggests the models cannot cope with tight curves

I had the same problem with some of my Farish Class 47 models, which made me think it was model specific

I had to reposition the curve, and that solved the problem

Edited May 25, 2017 by mjkerr

[philiprporter]

Sadly this suggests the models cannot cope with tight curves

I had the same problem with some of my Farish Class 47 models, which made me think it was model specific

I had to reposition the curve, and that solved the problem

Same issue for me (Farish class 47) and same solution - re-lay the curve with a gentler radius. 

[Gremlin]

40cm radius too sharp??  Very disappointing as a friend has his HO A4s going around the same radius without problems, would have thought/hoped that N could cope with that...

[philiprporter]

40cm radius too sharp??  Very disappointing as a friend has his HO A4s going around the same radius without problems, would have thought/hoped that N could cope with that...

Does seem odd as that's not exactly a crazy tight radius. One additional issue I had is that my track wasn't laid completely 100% flat where the curve started and there was no transition curve, but only Farish class 47s had an issue for some reason. I agree that it does sound odd because you say your track is flat and even Farish 1-co-co-1's traverse 9 inch set track curves without any problems. Superelevation may help? My curves are superelevated but it was the transition from superelevated to flat track that caused a lack of flatness I think and for some reason that and the tight radius upset the 47s so probably best to make sure there is a real gentle transition from flat to super elevated.

[Kris]

Does the lifting always happen at the same point on the track? If so is this on a joint, if it is it make be that this joint is causing the problem. 

 

Where the bogie wheels are not turning, this is not totally uncommon. A lack of weight on the bogie can cause it, as can a slight bit of flash on the plastic of bogie.

[Gremlin]

Does the lifting always happen at the same point on the track? If so is this on a joint, if it is it make be that this joint is causing the problem. 

 

Where the bogie wheels are not turning, this is not totally uncommon. A lack of weight on the bogie can cause it, as can a slight bit of flash on the plastic of bogie.

It happens on all four curves at different points...

[Kris]

Have you checked to see how easily the wheels on the bogies turn? Do the even slightly catch at any point, this could be enough to stop them when there is less / uneven pressure through corners. 

[Gremlin]

Have you checked to see how easily the wheels on the bogies turn? Do the even slightly catch at any point, this could be enough to stop them when there is less / uneven pressure through corners. 

They seem to turn without any problem...can't feel any friction or catching and it is always the leading axle, no matter which loco is running...

[Chris M]

Try checking the back to backs of the wheels. Probably won't help but if they are just a fraction too wide it could cause a problem. Also check the bodie is completely free to move around.