Hornby pendolino dcc ready derailing problem.

[drew13]

Hi guys im new to posting on here. I have a Hornby pendolino alstrom dcc ready version that seems to have a derailment issue. Travelling with the drive car at the front seems to be worse. The front bogey seems to under rotate and de rail. I cannot seem to find an issue but im rather new to the hobby. It derails quick and at slower speeds in this direction. But with the drive engine travelling to the rear it seems to travel much better with less derailments, but it still doesnt get rid of the problem. Any help would be great as id like to learn to fix problems myself rather than sending it away to be fixed and learning nothing in the progress.

[Pete the Elaner]

My first port of call would be to check the back-to-backs. This is the distance between the wheels themselves. They slide along the axles.

You would think these are set correctly by the manufacturer, but they can be a bit random & can vary within a loco/coach.

 

Back-to-back gauges are available from several manufacturers so you should be able to get one from a medium-sized show.

[34theletterbetweenB&D]

Welcome aboard to the good ship madhouse.

 

Careful observation of what actually happens as the bogie derails is key to understanding. As it is happening when pulling the train, it could be something to do with the coupling to the train behind. If that is holding the vehicle straight ahead when in tension, that could cause the leading bogie to come off. The fact that the vehicle stays on the rails when pushing the train argues that considered as a vehicle alone there is no fundamental problem. Can you run the leading vehicle alone over the curves where it always shows the problem, to see if it still occurs when not pulling a train?

[drew13]

i can do that today yes. ill do a few experiments with the position of coaches and the drive unit alone and see if there are any similarities or differences and get back to you. 

[MartynJPearson]

No experience with this unit, but two thoughts from derailing experience.

 

First is probably least likely but an easy check, as surely nobody would be as stupid as me - I put the body back on a loco and test ran it and it kept derailing, realised the body screws which I had not tightened meant that the bogies couldn't turn on the corners.

 

I've also noticed on a Bachmann 108 that the bogies have metal strips effectively sticking up to join with horizontal metal strips on the body underside, this is how the power gets from the bogie to the motor / electronics. If the bogies are turned too far, the upward pointing strips catch on the edge of the horizontal strips and stop the bogie returning back to a straight position. As I say, I have no idea how the Pendolino is constructed, but it might be worth checking to see if there something like that which could occasionally foul the movement of the bogie.

[Widnes Model Centre]

Chances are with this particular model, they coupling is jamming. Try moving the coupling and make sure it is moving freely.

[drew13]

Ok guys sorry its been a while. I measured the back to back of one axle and it was out. So i decided to purchase the back to back gauge for 00 gauge from dcc concepts. Cost me a little less than £10 and arrived in less than 24 hours. I checked every axle and everyone was out. So i spent an hour removing each one and adjusting until the correct dimension was achieved. Ive check all the couplings and they seem fine. Ive added a dcc decoder to both dummy and drive car now. I will test the loco again tomorrow and see how it performs

[drew13]

Ok so that hasnt solved the problem either. The track isnt tacked down yet but it on a hard flat surface of ply. If i tack the track down and eliminate any movement in track and make sure even though its new setrack that its clean and that doesnt solve the problem what should i try next to logically eliminate posibilities. ive also tried the loco as a 5 car rake and as the drive car alone and the problem is the same. at high speed its as if it stops turning into a corner and goes straight off the track. 

Edited January 21, 2018 by drew13

[TRAILRAGE]

Interesting. I've had a 9 coach Pendolino For several years and not had this issue. My issue was that I could only run it forward as because as soon as I ran it Motor pushing the thing would derail. For the love of me I couldn't figure out why so in the end purchased a second powered Chassis for the non motored end. I guess the weight of the train was to much for the Motorbogie and which may well have caused it to lift under power because as soon as I had fitted the second powered chassis it stopped doing it. Have you checked the actual chassis on its own to see if it still derails? it may give you a better understanding of why its doing it as the motor bogie is clipped in from the top so there is a possibility of something inside limiting he amount of bogie swing or that it is snagging on something. a smaal plastic burr on the bogie mount maybe.

 

Annoyingly I was having the same issue as your having but with a DJM 71. in the end I relaid most of the track which seems to have cured it at least for the moment. 

 

hope it becomes clear soon as I'm intrigued as to why it is doing it.

 

good luck.

 

Cheers Trailrage

[drew13]

Yes i tried the drive car alone and it did the same thing. I double checked how much the bogie could swing and it seemed to be slightly less than the dummy car. So i slightly loosened the screw underneath the bogie anf it turns a little more now. So ill be testing it tomorrow and i will get back to you. If i can help anyone else from my tests then im pleased to have done it

[drew13]

So i tested again today with the changes, and when i get to around 85 90% power it derails ive noticed that at high speed it rolls outwards like a lorry going round a corner to fast. And that was just the drive car. I tried adding a little weight lower down inside to lower the centre of gravity but the problem stayed the same

[TRAILRAGE]

What radius curves are you using ? As this may be part of the cause. When I first got mine it was when it was released and my layout used stupidly tight curves down to lack of space. I think they were 18"- "24" radius.

 

Nowadays I use 3ft- 4ft radius so no longer an issue.

 

Cheers Trailrage

[drew13]

im using 4th radius double curves. since all the adjustments it does run alot better, just isnt capable of successful full speed operation. but until i get started on my loft layout im stuck with the track i have. ill be using flex track with much greater radii. ive thought about banking the corners also to see if that helps with the rolling outwards at high speed. ill experiment with that at some point properly

[drew13]

So ive been working at this on and off and have come to the conclusion that i wont ever be running this loco full apeed anyway so the last 10% speed is not a problem. I will adjust the cv to lower the top speed so it never reaches the threshold of derailment.