Locos stalling on points

[Brian-1209034]

Hi everyone,

Just getting back into the hobby after many years, and therefore DCC and other improvements are a bit of a learning curve for me.

I started out this time with the Mixed Traffic set (R1236) which from what I see, is a good way to restart. I have not connected the full layout yet because I have not sorted out a baseboard. I have however had a little play with a few sections of track laid out on the kitchen counter top. (Could not wait to try it out.)

I noticed immediately that both locos do not like driving over the points, stalling at anything other than very high speed. I've checked all the track connections which are all solid, and also checked the current integrity with a multi meter. I've run my thumb over all the joints to see that no connection is standing proud.

I read somewhere that the Peco equivalent points are much better because the flange ways are deeper, but when I bought and tried one, there was no difference.

The set is brand new and shouldn't really need cleaning, but a cursory check of the wheels and track seem ok. I may be wrong, but now I'm starting to think that the problem lies in the locos.

Any thoughts on the matter would be appreciated, as if I can't fix this problem, then I see now point of going any further, building a baseboard and expanding the layout etc.

Cheers

BB

[Chrissaf]

I do agree that the contents of the set should just work.

But you have to be aware of some of the issues with sets. In essence they are put together with the cheapest lowest cost parts that can be sourced from the Hornby portfolio. In many sets, the locos are made very cheaply specifically for sets. This particular set has two 0-6-0 locos in it. The cheap Hornby 0-6-0 and even more so the Hornby 0-4-0 locos have a very consistent reputation for stalling over Hornby points.

You will find a multitude of threads on this forum asking for ways to overcome this issue. The most common suggested fix is to add additional track pins close to the frog area of the points [new pilot hole required] to flatten the point against the baseboard. In your described situation you are using loose laid unfixed track which of course eliminates that potential fix as being an option to try at this time.

For DCC layouts, the absolute 'Rolls Royce' technical solution is to fit the 0-6-0 loco decoder with a 'Stay Alive' capacitor. Very fine soldering skills are required for this option, unless you change the Hornby fitted decoder for a different brand decoder that has the 'Stay Alive' capability as a factory fitted option. A third common solution is to add a permanently wired wagon behind the 0-6-0 loco fitted with additional pickups to supplement the pick-ups on the loco.

It should also be noted that the multitude of threads on this forum that raise 'loco stalling' on points issues are typically DCC locos that are affected and in many cases not just short wheelbase locos. Multi-wheel DCC Steam locos are raised as issue posts quite often too. The Hornby track designs have not been updated for decades and pre-date DCC by some considerable time. DCC is definitely more sensitive to track condition than Analogue DC.

The best solution that I can suggest is to either fit a 'stay alive' to the existing decoder [fine soldering skills required] for which there are threads on this forum describing 'how' or replace the decoder with a different branded decoder that come with a factory fitted 'stay alive' option.

The function of the 'stay alive' capacitor is to act like a very small rechargeable battery that fills in the gaps in the electrical track supply to drive the loco motor past the location of the power break. The µF value of the capacitor defines how far the loco can travel without track power. Super Capacitors can drive a loco for several metres past the point where power is lost. However, these require a lot of space in the loco and would not suit a small 0-6-0 loco. A more modest 'Stay Alive' with just enough power storage for a few cm of unpowered travel will more than suffice to cover points.

[Howbi]

@Brian........It is important with new locos to run them in, ideally on a rolling road, about 30 minutes in each direction to free up the mechanisms which improves the slow speed running especially over the points. The real benefit of the Peco point compared to Hornby is the length of the plastic frog - it is a tad shorter.

However, it is rarely mentioned that on the 3 axle chassis crossing a point there are at least 5 wheels touching the railhead, 3 on one side and 2 on the frog side so really, as all the wheels have pickups, there should be no stalling but in reality there is. In my experience I found a great improvement by pinning the center of the point as advised by Chrissaf.

[Brian-1209034]

Thank you both for the information.

@Chris. I'm still a little confused. Obviously, the locos are not picking up something, either current or code, and I'm not sure which. I originally discounted lack of current because a multi meter showed a reading all the way through the points. The fixes you mention are way beyond my skill and knowledge levels, so I would have to employ a Hornby service agent to fit the stay awake capacitor or complete new decoder; someone like Southern Model Supplies. One thing is for certain, that the problem exists with Hornby and Peco points, so it must be the locos, which you confirmed.

@Howbi. I had come across this "running in" advice mentioned somewhere, but the reason I have not tried this yet, is until I build a baseboard, I have nowhere to lay out an oval. All my floors with a 6 x 4 foot space, are carpeted. I'll see if I can find a nice smooth and level piece of concrete out the back.

Once again, thank you both for the information.

Cheers

BB

[Chrissaf]

Obviously, the locos are not picking up something, either current or code, and I'm not sure which.

 

 

Definitely current. The way that DCC works is that the decoder remembers the last DCC command given to it. It will execute that last command until given a new command to do something different. If there is a short break in the current, then the decoder will re-instate that last previous command when the current from the track comes back on line.

These type of breaks in the current will not be found using a meter on the track. The break arises due to the inability of the loco to maintain complete electrical contact on all wheel pickups between the wheels and the rails. Cheap locos can have fairly rigid suspension, so if the rails are not completely 100% flat when distributed across the plastic frog area of a point**, then there can be a slight lifting of a wheel [that you cannot detect visually] which breaks the electrical circuit to the decoder. This is why the additional pin in the point frog area can in some circumstances be an effective solution.

Note** The plastic frog is in essence a break in a continuation of a flat rail. The loco wheel that is traversing the frog can either fall into the trough of the frog or rise up on the frog plastic. In either case, the slight displacement of the wheel traversing the frog can, if the loco suspension is too rigid, cause the other wheel to rail contacts to become compromised.

[Brian-1209034]

Thanks Chris, I'm starting to get the picture. I can see that the lifting of the wheel would only need to be microscopic to break contact. I'll go away and think about that. I'm slowly climbing the learning curve, with your help of course. Thanks for that.

Cheers

BB

[pd91223]

@Chrissaf

Might extra weight in the loco help to avoid lifting? Possibly easier to add weights in the confined space of a 0-4-0/0-6-0 than a stay alive.

[Flashbang]

Hi

Just to be sure on this..... Is the loco stalling or is it tripping out the DCC system momentarily?

Both of course cause the loco to stop, but the latter is due to something completely different.

[Brian-1209034]

Hi Flashbang,

I wouldn't know how to tell the difference. All I can say is that the other loco will still run at the same time, further down the track. When the loco stalls, even a gentle prod with the finger will not start it. I need to push it clear of the points. It does not have any problem with the points when approached with some speed.

[Chrissaf]

I wouldn't know how to tell the difference.

 

 

You are describing a 'stall'. If it was the controller tripping due to a short, then ALL locos that are running would stop.

[Mac-_-]

Brian, you say having to push it clear of the points, do you have IRJ's separating the points from the rest of the lay out?

[RDS]

It does not have any problem with the points when approached with some speed.

 

 

That is just the momentum that has built up, that is allowing it to continue. The way I always check if a Loco stalls when going over Points, is to go very slowly. If one particular wheel stops on the plastic part of the Point, it suggests that that wheel is the one that normally provides power to the Motor and that maybe the other wheels on that same side of the Loco, are not making good contact.

If that is the case, ensure that there is good contact between each wheel and it's pickup.

[morairamike]

Is this problem when the points are set for straight thru or when set to diverge or both.

If the other loco continues to run when one stops then I'd say the power is still there.

If your points aren't level then the loco can loose contact due to it rocking. You can check this by pushing the loco thru the points slowly and watching what happens as each of the wheels traverse the frog. Note that the loco can rotate in azimuth as well as rock.

Other thing to look for as you push the loco thru the points is, does it jam against the small guide rail and fitted between the rails. As you push the loco check for binding of the back of the wheel flange against the guide rail. I have a Castle class, that did just that, the centre drive wheels. Due to back to back being out. Gently opened up the b-2-b and tickled the guide rail face with a fine file. Problem fixed.

[Brian-1209034]

Brian, you say having to push it clear of the points, do you have IRJ's separating the points from the rest of the lay out?

 

 

No Mac, in fact the opposite. I have those very small springs fitted (correctly) between the points rails. My reasoning being, that with DCC I wouldn't need to isolate sidings.

A quick experiment with a weight (C type battery) Blue tacked to the loco roof improved this problem slightly. I will experiment with a heavier weight when I can find a way to fix it temporarily, although it might be a wast of time as I don't know how much room there is under the loco shell. I think it would have to be lead.

[Brian-1209034]

Is this problem when the points are set for straight thru or when set to diverge or both.

It occurs when approaching from all three directions.

Other thing to look for as you push the loco thrubyyd points is, does it jam against the small guide rail and fitted between the rails. As you push the loco check for binding of the back of the wheel flange against the guide rail.

I'll look if I can see if that's happening.