Heljan Manning Wardle derailing

[Alan Roberts]

PLEASE! Can someone assist me in trying to cure my MW TAW from derailing on SOME points. I've tried adjusting
The springs over the pony trucks, but it still persists in doing so.  Also the slightest imperfection in track level results in stalling while the wheels spin.  It's not as if the wheelbase is long, the driving wheels are quite close to each other.

[Hobby]

Back to backs?

Re the undulation bit that's a known issue on them, it's the pny trucks lifting the main driving wheels off the track. There is a cure but I don't remember what it is. If your are a member of NGRM PaulRhB of that parish has done a full run down of the issues and his fixes on the MW thread on that forum.

[B.Meldon]

There is a solution, but you will not like it!
Remove the pony truck springs/pickups.
Replace the pony trucks with ones made from metal, formed out of a block of lead will do.
Make the truck so that there is no side movement by the axle/wheels and that the only movement is in the pony truck pivot.
Replace the pony truck wheels with ones that do not have a flat edge to the wheel flange. (I think Graham Farrish have wheels of the right size?)
Ensure that the new pony trucks are free to move up and down also rock side to side.
The weight of metal pony truck will keep it on the rails, the wheels will no longer ride up on the flat edge of the flange and six-wheel pickup is enough for good running.
There is one final thing you can do but it is not at all easy and may not be needed unless you have tight curves, that is to move the pony truck pivot closer to the driving wheels.
See I told you that you would not like it!

[Alan Roberts]

Thanks for the info, you are right, I don't like it.  I think the lead pony truck is a bit beyond my caperbilities.
I may try to get some Farrish wheels though.

[Ian Bell]

The latest ones that they have just released were supposed to have been retooled to solve problems. Anyone tried them yet ?

[Crichworkshop2000]

I've played with my loco and got it running much better last weekend. This involved adjusting the back to back of the pony wheels as they were slightly wide. The wheel centres have blind holes for the axles so requires drilling through the wheel centres. As mentioned above to adjust the springs. The other thing I did was to slightly carve out the inside of the frames where the pony wheels touch to allow a bit more sideways movement. This  seems to help on 12" radius curves. The next thing I'm thinking of doing is to file the buffer beam a little bit to allow the pony wheel a bit more movement upwards and somehow alter the cow  catcher to allow a bit more downward movement as well

[Martin Collins]

Agreeing with most of the above.  I've got one of the Mark 1 versions which had all the known problems, of which the derailing/stalling was the most annoying.  Part of the problem seemed to be that not only did the pony truck pivot, so did the axle within the truck and therefore the loco never approached a point with the wheels facing in the correct direction. 

First effort was to force a piece of brass tube into the pony truck still using the original wheel sets.  Slight improvement but not perfect.  In the end I seem to have cured this by making up completely new pony trucks from strip brass and a suitable sized piece of brass tube (as tight to the back to back will allow) and using Dundas 8mm wheels which have a much better profile than the Heljan ones.  Fitting my usual B & B couplings aggravated the lack of vertical movement, so I removed the cowcatchers, and filed out the buffer beam rebate, and so far, so good.  I'd still like to replace the cowcatchers though, as they are such an integral part of the look of the loco.  Might try a Langley etched brass offering instead......

None of this should be necessary on a nearly £200 loco however.

Good luck.