Model Railway Forum

I have a class 43 HST set. It mostly runs fine. It leaves an oily trail behind it (not my fault - it came that way) but over time that should cease. Unfortunately there's one section of my track that it can't handle.

This is at the bottom of an incline. The incline easement goes straight into a curve. There is a very (very) slight incline at the rail joiner. It's so slight that you can't see it by eye and can only tell it's there by laying a metal ruler across the rails.

All the rest of my rolling stock couldn't care less. Up/down, fast/slow it's no big deal. But my HST lead car will not reverse into the curve (it can climb it just fine). The rear bogie is fine but the front bogie always derails. After investigating it I can see why. When sat on level track the wheels of the front bogie are almost rubbing on the chassis underside. This means they have no vertical travel so when the front bogie is straddling the above join the flanges of the rear set of wheels are just high enough to clear the rail top. Because the rear of the loco is on a curve the front bogie swings out to the left and now you've got a derailment.

Having taken the loco apart as far as I dare I can't see how to resolve it. It seems like the front motor is just set too high. The only thing I could do would be to cut off the front lower chassis cover and run with the pickups/worm drive more exposed.

Alternatively I could try and get Dapol to fix it as it's under warranty but I was wondering if anyone else could suggest something.

Photos front and rear:


And a video showing the problem:
https://photos.app.goo.gl/GhBfUzfnyLCHjgUo9

If it is under warranty don’t mess around with it send it back. Do you think it is a fault or is the gradient causing it?

I can’t help but think it’s the track not the loco. A combination of incline, transition from flat to slope and a curve all at the same point - no wonder the bogie can’t cope, it’s not designed to.

Agree Steve. Gradients can be more trouble than they are worth. They need a long straight approach.

I'd argue it's the loco at fault. There is clearly zero vertical movement in that front bogie when the back is raised. While I was taking that video I tried several times and it's simply not possible to lift the rear of the loco without causing the back pair of the front bogie's wheels to raise. I actually think that the front wheels might be rubbing on the bottom of the chassis but I just haven't run it for long enough yet for marks to be visible. If they aren't rubbing all the time then it's a miracle and for sure every slight bump in the track will be causing them to touch.

No other rolling stock or locomotive cares about that track join - I've been running all of them this weekend as the first opportunity to operate the layout in all its glory. I've got old short coaches, new long coaches, bogied wagons, non bogied wagons, a triple bogie diesel, two more double bogied diesels and my 4-6-2. The other four coaches and dummy rear loco for the HST are all perfectly happy. It's only that one lead HST locomotive that has the problem.

And when I say it's a slight incline at that point it really is very, very slight. It is invisible to the naked eye. Even laying a metal ruler over it barely shows a sliver of light.

But I am sceptical about a warranty claim. It runs fine on level track and the wheels touching the underside occasionally would probably not be an issue for most. But to blame my incline is I think incorrect. If a locomotive can't handle such a tiny, tiny change as that when everything else is happy then the fault seems pretty clear. And it cannot be right that there is no vertical movement available on a bogie.

Anyway I might fire off an email to Dapol but they haven't bothered to respond to my query about the excessive oil so it doesn't inspire confidence. For now I'll leave that loco on a small stub siding at the bottom of the incline and use shunters to deliver its coaches to it. I can call it The Dunce's Siding

Eventually assuming Dapol continue with their current absence of customer care I'll cut off the front section of the undercarriage where the front half of the bogie is touching. That should give it a couple of mm of movement and solve the problem. But it's another black mark for Dapol as far as I'm concerned.

Steve M wrote: ↑Sat Jan 30, 2021 4:40 pm I can’t help but think it’s the track not the loco. A combination of incline, transition from flat to slope and a curve all at the same point - no wonder the bogie can’t cope, it’s not designed to.

100% correct Steve, the OP has trouble with just about everything he touches, i think hes modelling the wrong scale. I give up reading his posts from now on. You can lead a horse to water.

Fair enough but with OO the track needs to be be very flat, with N it is even more important. I’m not convinced there should be a lot of play when you lift the loco. On my O gauge layout I had a spot where one loco always derailed, everything else was fine. The track looked perfect. I placed a thin piece of plastic under that spot and the loco was fine, and as I said that was with O.

There isn't a great deal of play on the bogies that work but there's zero with that particular bogie and that can't be right. If there's no vertical movement then the loco cannot climb an incline. Period. Nothing in the Dapol documentation claims that the loco can only be used on the flat and the rest of its train is fine.

For what it's worth here are two more videos:

Me pushing the unpowered dummy loco down the incline at fairly high speed. Bear in mind when watching it that the dummy loco does still have power pickups because you can fit a second decoder to control the lights.
https://photos.app.goo.gl/yYmLuU5ZHue5TyZL7

The troublesome loco at relatively low speed:
https://photos.app.goo.gl/KRx7pSKfsheygTqy5

It's difficult to get a shot of that joint because it's in the middle of the board but it's actually flatter than I described. The end of the curve and the end of the incline (the joint itself) are glued to the same piece of plywood and both were well weighted down while the glue dried. The plywood itself is at a slight angle because it has to accommodate the beginning of the incline but it doesn't look to me like anything serious.

Anyway I wasn't looking to start an argument, just hoping that someone would be able to say 'Oh sure, I had a similar issue and you can fix it like this..'.

brian1951 wrote: ↑Sat Jan 30, 2021 5:22 pm

Steve M wrote: ↑Sat Jan 30, 2021 4:40 pm I can’t help but think it’s the track not the loco. A combination of incline, transition from flat to slope and a curve all at the same point - no wonder the bogie can’t cope, it’s not designed to.

100% correct Steve, the OP has trouble with just about everything he touches, i think hes modelling the wrong scale. I give up reading his posts from now on. You can lead a horse to water.

Wow. Great response from the site admin. What a crappy way to operate a bulletin board. Well I shall bother you no more. There are plenty of other bulletin boards where people aren't so arrogant and rude to their guests.

-but none more knowledgeable. Quality of advice given on here, will not be bettered elsewhere. particularly, for N gauge..