Loco Stalling & Voltage

[The Captain90]

Have a loco that stalls on an electrofrog point - but only when it crossing slowly (tortise pace). Upon checking voltage it appears the frog is putting out 13.5 volts compared to the rest of the layout's 15.5 volts. Is a reduction of 2 volts enough to stall a loco? Will of course look as to why voltage is down in due course.

[2e0dtoeric]

First off, what sort of loco? I'm guessing a shunter of some description.

So - first check is that the pick-ups on the backs of the wheels are really picking anything up! Cleaning or wear could have distorted them very slightly, so as the wheels deflect sideways the contact is broken.

Next, when moving at very low speeds, it only needs a speck of muck, a tiny ripple in the track, or an insulated gap, to leave one wheel with no electrical continuity, so if the comment above is true, then the motor will stop.

I doubt that a 2v drop will make much difference, but it is something to look into.

Are you using a bus under the boards, or relying on the track to provide power all over the layout?

If you are relying on the track, it could be a slack fish-plate, and as the loco moves over the joint, the track moves microscopically, and breaks the circuit, (as in 'Next').

[Chrissaf]

As you know Captain, from previous questions and answers, I use Electrofrogs with switched power frogs. All my locos traverse the points without any major issues at most speeds. All that is except one. A 0-6-0 Hornby 08 shunter. It is on its second set of pickups (fitted by a service centre not me) and still occasionally hesitates on certain points. It could really benefit from a stay-alive, but all the available internal space is taken up with a Loksound V3.5 decoder and speaker. Powered Electrofrogs are good, but they can't provide 100% protection for a loco with an intermittent pickup issue.

[RDS]

I have 32 sets of points on my layout and they are all the standard Hornby insulated ones. I used to have problems with small Shunters but this has been dramatically improved by adding another track pin, in the middle of the troublesome points. A new hole (1.3mm) was drilled in the centre of the middle sleeper. The points I modified were the ones that had even the slightest hint of vertical movement.

 

It worked for me but laying your points exactly flat is good practice.