Locomotive and Coach Suspension Queries and advice

[J Gleeson]

I am converting RTR locomotives to P4. It appears that there are P4 locomotives running with straight wheel changeouts-ie no suspension. I would be interested to hear members views on this, as I wish to convert my stock as economically as possible-ie use as much of the model components as possible.
I have a PDK kit which has a one-piece fold up tender chassis with fixed bearings-has anyone converted these chassis to P4; here I am considering one fixed axle and beam compensation, if that is possible.
All observations and advice most welcome.
I also note that RTR coaches are running with straight wheel changeout-what are members experiences with such stock?


I look forward to your comments.

J Gleeson (Member 3721)

[chrisf]

This is a laudable objective. However, the range of variables is almost infinite. For example, how good or otherwise is the track on which the conversions are to run? I would rather build in suspension than have to retrofit but predict with confidence that others, with much more experience, will disagree.

Chris

[Terry Bendall]

I am converting RTR locomotives to P4.

Models of steam locos or diesel?

If the latter then no problems at all as long as the wheels are concentric and square on the axles. I hve not dine any steam loc conversions but the general view is that there are generally few problems.

I also note that RTR coaches are running with straight wheel changeout-what are members experiences with such stock

limited experience but again no problems

Terry Bendall

[billbedford]

I also note that RTR coaches are running with straight wheel changeout-what are members experiences with such stock?

Putting steel steel pin point axles into plastic bogie mouldings will lead to the plastic wearing. Whether this will be a problem will depend on how much running your stock will do.

[Noel]

Putting steel steel pin point axles into plastic bogie mouldings will lead to the plastic wearing. Whether this will be a problem will depend on how much running your stock will do.

I suggest that this is not a real problem, since the r-t-r coach would have arrived with steel pinpoint axles in the plastic bogie, else the straight swap would not have been possible. Presumably the r-t-r manufacturer can be relied upon to use appropriate materials?

[Penrhos1920]

It really depends on the model you're starting with. Some diesels are a nightmare, Bachmann 37, 66 K 47. Others are ok.

With rtf coaches I find about 1 in 10 bogies just won't convert and need to be replaced with a sprung bogie. Even though they are all made in the same mould some end up with axles that aren't parallel

PS the quality of the replacement axles has something to do with it. Ultrascale and black bottle are the best, intercity rollers the worst (because they come pre weathered and you have to remove dirt off the tread.

[grovenor-2685]

Even though they are all made in the same mould some end up with axles that aren't parallel

I don't think they are all made in the same mould, I have noticed several versions of the Bachmann mk1 (B1) bogies.
Most but not all taking replacement wheelsets with good results.
Regards

[Philip Hall]

I would emphasise Terry's comment about concentric wheels. This is an absolute must when converting RTR engines and stock to P4. Although we would be unlikely to try and build a rigid chassis for P4, the amount of movement in a commercial job means that steam engines are readily convertible, given decent track and true wheels. There is little leeway with our little flanges for a chassis to rock on its wheels.

As a starter, I suggest one of the Ultrascale sets fitted to a modern RTR steam engine. It is also best to test the intended victim to make sure it runs as smoothly as you would wish before you start taking it apart and throwing the guarantee out of the workshop window. If it runs badly in 00, converting it to P4 won't cure it and will be the cause of much frustration.

Philip

[J Gleeson]

Many thanks for taking the trouble-this is obviously a complex subject, and I will follow up. i am interested to hear of any experiences with changeout P4 wheels on RTR locomotives

[Philip Hall]

There has been quite a bit on here about conversions In the past, some of it written by yours truly and by others who have been doing this sort of thing for years. Have a trawl through the history on the 'steam locomotive' section and you should find help. There have been articles in the press as well, mostly in MRJ. Another useful source are Pete Hill's conversion pages on the Alan Gibson website which although for EM, are full of sound practical advice just as applicable to P4.

Philip

[J Gleeson]

Thanks, Phillip, much appreciated. I will follow that up.

[David Thorpe]

I've rewheeled several Bachmann coaches using the original RTR bogies with Gibson coach wheels. I recall that some of the bogies needed to have some plastic carved away from the inner surfaces to allow sufficient clearance for the wheels, but once done all run well. As I only have a small end-to-end layout they're never going to achieve much mileage so I'm not worried about the pinpoint axles wearing away the plastic. Short wheelbase freight vehicles can also be successfully converted with replacement wheels, although they often won't "drop in" until the brakes and even axle boxes in some cases have been adjusted. They also need to be sufficiently weighted to achieve decent running.

I've also rewheeled a Hornby Black 5 using the Gibson conversion wheelset. I think I was helped by a thread on RMWeb, but it was fairly simple and the completed loco ran well, as did that of a friend of mine who did the same thing. Considerably simpler was the Bachmann class 24 diesel (Gibson wheels again) where the excellent instructions on Keith Norgrove's website were invaluable.

DT