A1 / A4 tender causing problems

[KL1707822813]

Hello,

I've noticed a couple of problems with A1 (R 3989 'Knight of the Thistle') and A4 tenders (from R 2798 'Merlin') that I have.

Both of them short out going from a radius 3 curve points into the inside radius 2 curve. I think one of the tender wheels is causing the problem just as it gets to the frog.

The A4 tender - which I think is older and doesn't have a wired connections to the main engine - seems to stop the engine at a standard point I have on my layout. It's always the same place, perhaps suggesting there is a power issue there? It only happens when the engine is quite slow (but that's not the point of an A4, right?)

Both engines are not problems when they are run without the tenders. I don't have any other tender engines (yet!) to test out if it is these 8-wheel tenders that are the problem.

Any help would be appreciated!

[ColinB]

I have had issues with the old style pin and twin wire connector on the drawbar shorting out. In the end I replaced them with the new 4 wire connector. It could be the pickups on the tender touching the axles of the wheels at the back end where they bend. Other that that horrible drawbar generally the tenders are not an issue. I have had problems with the back end pickup on the loco touching the chassis where the paint has come off the pickup. It may that the tender puts more weight on the back end of the loco to cause it. Other than that they generally are one of the more reliable locos.

[96RAF]

This is the twin prong and post arrangement Colin speaks to.

I have stripped off the electrical parts on a couple of locos to make it a simple drawbar and as Colin did installed the later standard X6113 4-pin plug and socket, which needs a bit of soldering, etc.

A bent drawbar can as stated bias the driver wheels up or down front or back.

[KL1707822813]

Thanks for the advice. I had a think about the drawbar and back end of the engine being moved up and down, as this seemed a place to start before getting into wiring. A bit of jiggling track later to smooth things out and close up some gaps between tracks and it all seems to be working fine.