On Ravensers Bookcase

The glum appearance of those drooping windows at the front is enough to indicate that these locos were not going to work well

 

I've had all the same problems with those ring-field drives, when I use them for tender driven small pre-grouping engines.  gears slip and traction tyres don't pick up.  Has anyone made conductive tyres?

 

 

It's a comfort to know that it's not just me - and that these are recognised issues. Also worth bringing them to people's attention, so the next poor bloke doesn't spend a week scratching his head

 

These ringfield motor bogies are never going to be in the same league as a modern centre-motor mechanism with drive to both bogies. That said, a reasonable performance can be extracted from them and there are no realistic readily available alternatives for a project like this, unless you can manage to source a Hornby Railroad motor bogie or possibly a Bull-Ant - if they are still available. Even those are going to be a step down from a modern diesel mechanism

 

Some of the EM modellers still seem to use ringfields (see Canada Wharf/Hornsey Broadway) but I think they have the advantage of rewheeling with Ultrascales - meaning full conductivity, an upgrade to the gear train, and the replacement final gears being professionally designed to mesh properly at the revised back to back.

 

Conductive traction tyres would be good, but I'm not sure how you'd do it. Carbon or graphite would conduct, but how you would come up with a traction tyre that wasn't hard or lubricated but would still conduct is an interesting question. Some sort of carbon paste used to infill the grove round the wheel???

Edited February 11, 2021 by Ravenser

One of the saving graces of the Margate Ringfield mechanism is that the traction tyred geared wheel is matched by a non-traction tyred geared wheel on the trailing bogie. For project locos using original chassis, I swap one traction tyred geared wheel on the motor bogie with a non-tyred wheel from my magic pile of spares and fit an extra pickup on that side. The trailing bogie gets all wheel pickups, and hey presto, 7 out of 8 wheels collect current. As long as the motor is cleaned, lubricated and nit hopelessly worn, they work remarkably well with a bit of extra weight - not obviously up to modern Bachmann/Heljan/Hornby full fat level but a very cheap supplement.

22 minutes ago, andyman7 said:

One of the saving graces of the Margate Ringfield mechanism is that the traction tyred geared wheel is matched by a non-traction tyred geared wheel on the trailing bogie. For project locos using original chassis, I swap one traction tyred geared wheel on the motor bogie with a non-tyred wheel from my magic pile of spares and fit an extra pickup on that side. The trailing bogie gets all wheel pickups, and hey presto, 7 out of 8 wheels collect current. As long as the motor is cleaned, lubricated and nit hopelessly worn, they work remarkably well with a bit of extra weight - not obviously up to modern Bachmann/Heljan/Hornby full fat level but a very cheap supplement.

 

A useful idea.

 

I'm toying with the idea of ordering an Ultrascale double motor rewheeling pack and using that to rewheel the motor bogies of both the NBL 21 and the Baby Deltic. However before I commit, I need to get the 29 I reworked and rewheeled years ago up and running on DCC. I can then be quite sure that the finer Ultrascale wheels won't cause any problems on my pointwork before I splash the cash.

 

Obviously there will then be a wait of some months before I actually get my order, but it's not an urgent job - the locos already run. And having had to press a tyre back on a wheel centre last time , it may prove necessary anyway. The thought also occurs that I would get a better quality final drive gear, and it would be designed to mesh properly at the wider back to back

I'm sure despite the wait it would further improve things. I see it as a sort of continuum from minor tweaking of the older mechs to replacement of components and additional functions such as lighting circuits and DCC fitment. I've no doubt that a full works final China 5 pole Ringfield dealt with in this way would be pretty decent. 
In my case, I have a rather large stash of Class 24s/25s being built out of Hornby and Bachmann bits and the self-determined aim is to create as many models as possible graded so that some at least are decent performers whilst others will work but not necessarily with fine control or decent traction; and a couple of dummies will emerge for depot placement or double heading.