Newly repaired loco doesn't like settrack points.

[AndrueC]

I sent my Queen Elizabeth 4-6-2 off to Bachman to be repaired. They have done as requested (quite quickly as well, less than three weeks) and the valve gear is now fine. Unfortunately she will no longer run on my layout in reverse. Every time she enters a turnout from the branch line her front bogey derails. She also derailed when attempting to cross an at-grade crossing on a straight stretch of track.

 

At a pinch I could remove the crossing (though I'd really rather not) but not being able to reverse is a serious limitation on my layout. All trains have to reverse in order to leave the staging area. And of all the locos I have she is the only steam engine and the one I want to manhandle the least.

 

Obviously I'm going to contact Bachman about it but I was just curious if anyone could think why and/or if there was anything I could do to avoid having to send her off again. I haven't looked closely yet but I'm using insulfrogs and I've noticed before that the insulated bit doesn't have much depth to it. Could it be that Bachman replaced the front bogey (I didn't ask them to) and the new one has deeper flanges?

[08221]

Have you checked the back to back on the wheels - if they are incorrect, it can be a constant cause of derailments.

[33C]

Does/did the front bogie have /had a spring pushing down on the pivot to add slight pressure and a modicum of steering to the bogie? It may have been removed/forgotten during the repair. I would also remove the bogie and add a bit of blue tac to it and push it through the offending points with a pen/stick lightly, and observe what is happening to it, free of the loco. If it runs through fine (back to backs), then the way it is mounted to the chassis is the problem. 

[Kris]

Don't Farish say that this loco is not suitable for first radius curves? (this is what your point is). If so it could be that they fixed a back to back when they serviced it, and it was the previous setting that allowed it to traverse your set track point. 

[AndrueC]

Thanks for the advice, everyone. I should have time tomorrow to remove the bogie and see how it goes on its own. The fact it derailed at the at-gauge crossing makes me wonder if the wheels are a bit too narrow. Those crossings don't have a very large margin for error.

 

I think I did read that the specs are 2nd radius only and I know she could never make it round a pair of back to back turnouts that I have on one siding even forwards. She has always grumbled a little bit traversing points (I still wonder why Peco made them 1st radius since the OO gauge versions are 2nd radius). She can still go across them forwards but reverse is hopeless.

 

What is this 'back to back' thing? Is it something I could adjust?

[grahame]

7 minutes ago, Kris said:

Don't Farish say that this loco is not suitable for first radius curves? (this is what your point is). If so it could be that they fixed a back to back when they serviced it, and it was the previous setting that allowed it to traverse your set track point. 

 

Quite possibly. It is a large loco with longish wheelbase and many are listed as unsuitable for less than R2 curves. I don't know whether that is the case for this loco. Although some listed as such will negotiate tighter bends, it is putting a strain on them with a potential for running problems to occur.

 

Also setrack points (which are R1) configured as a crossover form a S bend/reverse curve that will prove additionally tricky for long wheelbase stock. It would help and improve running if they were replaced with larger radius electrofrog points.

 

 

[08221]

Back to back is the distance between the inner faces of the wheels. There are specified measurements to ensure smooth running.

Its amazing what a difference a tiny error can make to the reliable running of any items of rolling stock.

[AndrueC]

Okay well I had ten minutes free this evening and have done some testing by gently pushing her along a turnout. I don't think the curve is the problem now. In this image I pushed her in reverse from right to left. At the point where that piece of black plastic is in the middle of the shot the back pair of her front wheels jumped off the rails.

She wasn't even on a curve, just going straight back. It looks to me like her wheels must have caught on the 'hinge'.

 

She did it on another couple of turnouts that I tried as well. The above turnout isn't the one I originally found the problem on, it was just a convenient turnout to test. For what it's worth here are other views of that turnout from other angles:

 

https://photos.app.goo.gl/csXWRRCE6FTTquW48

 

To my mind it suggests some kind of back to back problem as she didn't like the at-grade crossing. The front bogie is incredibly sloppy. It is attached by a tie-bar to the chassis and that's all. There's no central pivot. When poking the rear wheels with a small screwdriver it takes barely the slightly prod to lift them. Maybe adding some weight would help?

Edited April 23, 2021 by AndrueC

[08221]

Definitely check the back to backs. Where the bit of plastic is, there is a raised, marginally wider bit on the straight point blade. If the back to backs are too tight, it may be catching on that bit of rail and jumping.

 

if you get down to eye level, can you see the wheel lifting off?

[33C]

I would suggest a spring in the middle of the bogie to a small peg on the chassis. Use a cut down biro spring (start long!), stretch some sprue, or plastic rod, to the thickness you need to make 2 pegs. Glue a stump to the underside of the chassis,and push fit another stump into bogie pivot. This should push the bogie down on the rail and give a smooth pressure to guide/steer. The early "Hornby" 9F bogie arrangement is what i'm getting at or, the "Mainline" loco bogie springing arrangement. These are as simple as it gets and works for them! Good Luck!

[AndrueC]

Thanks for the comments, guys!

 

I did a bit of measuring today with a small piece of card (best I can do) and it appears that the QE's back to back is narrower than my other rolling stock. The piece of card now measures 7.5mm and just about slides between the wheels on the QE. On my Dapol stock it slides between with a little bit of slack. Obviously not very scientific but I would estimate that the QE back to back is 0.5mm narrower.

 

However I've also watched her closely on that turnout and the point where the rear bogey pair rises up is actually the cut-out where the points connect. I also saw it happen on the straight stretch of track just before the turnout but can't work out why. From poking with a small screwdriver there really is very, very little holding that bogey to the track.

 

I will investigate the solution that 33C made. Unfortunately I'm not sure if my modelling skills are up to it and I'm very loathe to damage the loco. It was hard enough finding her in the first place and she has nostalgic value (when I was a boy my Dad built a layout for me and my brother and gave me two Triang Princess Elizabeths so I've tried to recreate that train.

Edited April 24, 2021 by AndrueC

[AndrueC]

I think I've found the problem. There is no pivot on the front bogey.

 

https://photos.app.goo.gl/v2kM797XCAqFh14d9

 

I assume there's suppose to be a pin either on the underside of the chassis or the bogie itself. The question is do I try and put one on myself or see if Bachman Repairs accept that they caused it (it only arrived Friday) and take her back.

 

Edit: Hah. I just realised I forgot to check if the bogey hole went all the way through. If it does then perhaps all she's missing is a bogey pin. I've put her away now but next time I'll check if that might be the case.

Edited April 25, 2021 by AndrueC

[AndrueC]

I tried adding more weight to the front bogie but it didn't help. Here's a video of it happening:

 

https://photos.app.goo.gl/Evj18MHhDRe3zAmw5

 

The rear bogie wheel just can't be bothered to follow the rail. It's not so obvious in that video but by eye it looks like the wheel just decides it wants to climb the rail so it does.

Edited April 29, 2021 by AndrueC

[Dr Al]

Problem looks to be the sharp curve entering to the point - looks like the cylinders may be clashing with the bogie, as it's when you push onto the curve that that happens.

 

I suspect therefore you've hit the R1/R2 problem, and it may be Bachmann had the cylinders off to repair and reseated them a fraction differently so they are now catching.

 

Also, from your previous picture, the BTB on front wheels looks far too narrow -  this may not be helping, giving less lateral movement that it should have. I'd fix this first.

 

Cheers,

Alan

[AndrueC]

You're right @Dr Al! I just checked again and if I stop her just as the wheel is coming up and gently prod the wheel the whole loco moves which it shouldn't and the wheel resists the attempt to drop it back into place. It's very difficult to see but something (probably as you suggest the cylinders) is hitting the rear wheels.

 

That's a bit naff though as she's backing into an R2 curve from the straight part of a turnout. She should be able to negotiate that (Farish claim she can take an R2 curve). If she was coming round the turn out then that would be R1 -> R2 which she can do but has never been happy about.

[Dr Al]

Did you fix the back to back on that front wheelset? As I say it looked narrow, so that's likely wrong.

 

Cheers,

Alan

[AndrueC]

1 hour ago, Dr Al said:

Did you fix the back to back on that front wheelset? As I say it looked narrow, so that's likely wrong.

 

Cheers,

Alan

I tried but frankly I'm scared to. Also I think it's all the wheels causing the problem. She has a lot of play while sat on a curve and I can push her front end toward the inside of the curve at which point the bogey is released. I assume that if her chassis back to back was increased this would restrict the outward movement of her front end just enough to avoid the problem.

 

I think at this stage the only option is to send her back for further repairs. Hopefully Bachman will accept that they didn't fix her properly last time and will either repair her for free or only charge P&P. I don't know whether I'm more annoyed that I have to send her off again or irritated at what feels like a sloppy repair. To be fair she does run forward (in the absence of at-grade crossings) but now that I know about back-to-back it feels like someone didn't do their due diligence before declaring her repaired.

[Dr Al]

I wouldn't be afraid of moving the bogie wheel - it's just a push fit onto the axle.

 

Cheers,
Alan

[Steven B]

If you remove the bogie you'll be able to push it through the troublesome point without having to worry about clearances between wheels & cylinders (and remove the risk of causing further problems). It should be possible to see where the wheels are lifting from the track which might help identify if it is the wheelset's back-to-back or if there's something else going on.

 

To remove it, undo the the cross headed screw in this image:

https://photos.google.com/share/AF1QipObOpMfmYzFMk3tUUKlATkbqETdNJM8FJgMXBOfA6Ph95TVqI6H5zPQvraSAohwmA/photo/AF1QipPEYjiTlVBACdcTAt97o1EFcSHHXFcQp4Xv2npO?key=NEJXclZHMmdYdUtKOVBzbHNhMUw5TWJXU2c2ZjV3

 

Steven B.

[grahame]

On 03/05/2021 at 13:47, AndrueC said:

I think at this stage the only option is to send her back for further repairs. Hopefully Bachman will accept that they didn't fix her properly last time and will either repair her for free or only charge P&P.

 

Before sending it back I think it's worth checking out how the loco performs on R2 curves and R2 radius points in a similar configuration, otherwise it might appear you're expecting them to 'repair' the model so that it runs on R1 point work when they've specified the minimum is R2.

 

 

 

[AndrueC]

3 hours ago, grahame said:

 

Before sending it back I think it's worth checking out how the loco performs on R2 curves and R2 radius points in a similar configuration, otherwise it might appear you're expecting them to 'repair' the model so that it runs on R1 point work when they've specified the minimum is R2.

Thanks. Yes, I tried her at the start of one of my straights and she has the same problem reversing onto the curve - she derails every time. I don't have any R2 turnouts because mine are all settrack.

 

She will go forwards into an R2 corner. My guess is that when going forwards the forces acting against the front bogey are such that the path of least resistance is for her drive wheels to move inward. Either that or the bogey/cylinder contact dynamics are different enough to prevent the problem.

 

She used to be able to reverse out of my staging yard and I assume that the specification of 'supports R2' includes going in reverse.

[grahame]

25 minutes ago, AndrueC said:

Thanks. Yes, I tried her at the start of one of my straights and she has the same problem reversing onto the curve - she derails every time. I don't have any R2 turnouts because mine are all settrack.

 

 

And does it derail on R2 with the BtBs for all wheels checked and adjusted/corrected?

 

 

 

[AndrueC]

3 hours ago, grahame said:

 

And does it derail on R2 with the BtBs for all wheels checked and adjusted/corrected?

No idea. I'm too scared to try and adjust them. I know that it used to reverse just fine before its valve gear broke and it got sent off for repair.

 

Anyway Bachman servicing seems happy to have her back to try and sort it.

[33C]

I still think a spring is missing from the small locating hole in the chassis (shown earlier) that puts pressure on the bogie, to aid road holding, and guides the bogie through pointwork like the prototype.

[grahame]

33 minutes ago, AndrueC said:

No idea. I'm too scared to try and adjust them.

 

It's nothing to be scared of. You can get BtB gauges to assist and ensure the gap is correct but it's something you really need to get a grip of. Then you'll be able to check and adjust all your rolling stock and find that they will run better. 

 

BtBs can go out of gauge over time, through use, handling, if the model is sent in the post and so on. In fact many new models can be received needing the BtB to be tweaked/corrected.