Curve Radii

[steve howe]

I am planning a section of street tramway on my successor to Horsley Bank which has a short section of track in the background with a single tram on an automatic shuttle. (pic attached - apologies for lack of overhead wiring!!) The feature has proved so popular with viewers at shows that I want to develop a slightly more ambitious system using the Chris Cornell kits running on 16.5 track. The plan is to make two hidden 'dog bone' return loops at either end giving the appearance of double track on the visible section.

 

Can anyone advise me what the minimum practical radius is for tram curves in 4mm scale - bearing in mind they will not be seen? I seem to remember being told that 4" was practical - I intend running typical 4 wheel 'Preston' type trams (although the Leeds 'Feltham' vehicle is a tempting possibility!) The period is imediate pre-War2.

 

Steve

[meil]

(pic attached - apologies for lack of overhead wiring!!)

 

 

I assumed it was a stud contact system!

[PLD]

Hi Steve,

 

The answer really is 'it depends'... and not just on what types of cars you intend to run, but particularly for bogie cars also what type of chassis is underneath them.

 

A good example is Mark Casson's (Red Devil on this forum) 'Grime Street' - the radius of the inner circuit is about 4 inch which is OK for most 4 wheel cars but about the limit for longer wheelbases. The outer loop is close to 6 inch and his Feltham with just about squeeze round that on it's Halling chassis, but I doubt that you could go round that using either the Bachmann street car or the ABS motorising kit for the Corgi cars.

 

Paul

[Red Devil]

Steve, as per Paul's post, it does depend, you'll get pretty much any four wheel car (up to about 35mm/8'6''ish) round anything as tight as four inch radius but even then it depends on what sort of mechanism you use as to how well it will get round something as tight as that.

 

I now use (solely) Halling mechanisms as they will cruise round the very tight radius curves on 'Grime Street' without any noticible slowing and or possible stalling on the curves, I did one exhibition with assorted Bec/ABS etc mechanisms and came home and stripped them out and flogged them all on ebay! These seemed to need 'driving' round the corners to get them round, at a guess I'd say this is down to the inherant sloppiness in this sort of drive unit. With the Halling units slow speed running is much easier to achieve, they really are worth the extra £10/5 over a whitemetal chassised one (In my opinion).

 

As to bogie mechanisms, you would get a Feltham etc round a six inch curve using either bec trucks or a modified Halling/PC trams mechanism, but one running on Bachmann Brill adapted chassis probably wouldn't as there wouldn't be enough room for bogie swing. Again even then it could labour round a curve that tight. The othe option is the new Diablo and lightening drive from Hollywood foundry, but as yet I've not tried one (it looks very promising though).

 

I know Chris has recently brought out a covered top (Luton?) Preston type car kit, but also a convincing enclosed 4 wheeler can be made from the Tower E/1 kit by shortening the body by one window bay you can achive a 16ft body section and then mount it on a Brill/Peckham truck casting............

 

If you need any further info on Halling drives there's quite a bit in my Blog on here, hope that's some help.

 

Mark.

[steve howe]

Thanks for that Mark, I may be OK if I limit the stock to older 4 wheelers, the tramway is an adjunct to the main railway element of the layout so I won't get too hung up on specific types of tramcar. The one on Horsley Bank is actually a 'Matchbox' series so is slightly underscale but as it is in the background this is not a problem. I hacked it about and installed a Bec chassis which ran like a pig, the slop between the flanges was so excessive I soldered another length of rail inside one of the running rails to reduce the gauge! Constant running at shows - it shuttles back and forth about every 40 seconds - plus graphite on the railheads has improved running considerably but I'd never use Bec units again. Where do you get your Halling chassis? these certainly look to be the way to go, I have been told that Tenshodo bogies and Black Beetle units are good but have yet to roadtest one, also I am not sure if the wheelbases would be correct.

 

I also found the Easy Street website a while ago and was highly impressed with the components, although for the small amount of visible trackage I need I suspect I will use bullhead rail on copperclad sleepers with a strip of nickel silver bar representing the inside section. I recently got clobbered for import duty on a Walthers gasholder kit which makes getting 'reasonably priced' items from the US less attractive!

 

Thanks again for your guidance

Steve

[Red Devil]

Steve,

Halling drives are available in the UK from either 3mmSMR/Motorbogies.com or John Whitehouse at East Lancs Model Tramway supplies, http://homepages.tesco.net/j.d.whitehouse2/motor%20units.htm You can also get them direct from Halling, but with the pound doing so well againsrt the euro it's hardly worth bothering ordering direct with the higher postage costs. The vario one is probably the best bet for earlier trams withb shorter wheelbases as it can go from 24.5mm to 30.5mm, the 35 one is the one best suited to 8'6'' wheelbase cars like the EFE Horsfield, that is much lower profile. To be honest the Hallings are great for the price, better than the Tenshodo SPUDs as they aren't likely to strip gears. The Black Beetles are great, but a bit dearer.

 

If you do order from Proto87 stores expect to receive several packages from sunny California either in the same post or subsequent ones, I belive Andy Reichart is originally British and is well aware of UK Customs and Excise and the Royal Mails attempt to extort £8+ per package (or whatever it is) B)

 

Again hope that helps a bit.