0-8-0/2-8-2 minimum radius

Do you have a problem? Here is the place to appeal for help
Post Reply
User avatar
IrishPeter
Driver
Driver
Posts: 1400
Joined: Wed Feb 23, 2011 3:24 am
Location: 'Boro, VA

0-8-0/2-8-2 minimum radius

Post by IrishPeter » Sun Nov 25, 2018 4:12 pm

I have been playing around with the idea making SM32 versions of the Sierra Leone Diesels for a while, and whilst I have a fair feel for the size of the beast, what do we reckon for minimum radius? I usually work on the idea of 30 inches for an 0-4-0; 42" for an 0-6-0; so that leads me to conclude 54" for an 0-8-0 or 2-8-2 (assuming the carrying wheels are on pony trucks not radial axles. I am also assuming blind drivers on anything bigger than an 0-4-0. Anywhere in the ballpark? I noticed that Accucraft reckoned you could get their NG16s around a 4' radius curve but (a) I assume that is "at dead slow speed without gauge widening" as they used to say, and that (b) you can do it, but it isn't pretty.

Other opinions welcome and needed.

Cheers,
Peter in Va
Traffic Pattern? What pattern? Spuds out; grain in, but cattle, sheep and passengers are a lot less predictable.

Big Jim
Moderator
Moderator
Posts: 2694
Joined: Sat Jul 06, 2013 5:28 pm
Location: Near Llanelli

Re: 0-8-0/2-8-2 minimum radius

Post by Big Jim » Mon Nov 26, 2018 9:58 am

I think you may be right with the bit about the 4ft curves.
The line at the local ME club has a curve of around 36" radius and my RH Russell does get around it but it is obviously too small for the loco despite plain center driving wheels.
If at first you don't succeed, use a bigger hammer!

User avatar
GTB
Driver
Driver
Posts: 1550
Joined: Sat Mar 05, 2011 2:46 pm
Location: Australia

Re: 0-8-0/2-8-2 minimum radius

Post by GTB » Mon Nov 26, 2018 12:26 pm

It depends on both the wheelbase and the gauge of the model. An eight coupled chassis with flangless wheels on the 2nd and 3rd axles and a wheelbase of 140mm will just get around a 1.2m radius curve (LGB R3) on 45mm gauge track.

You might get the Accucraft NG15 to squeeze around a 1.2m radius curve on 45mm gauge, but it would be less likely on 32mm gauge, as there is less clearance (slop) between the wheel flanges and the inside of the rail head in the smaller gauge. Accucraft have made several large ng US eight coupled locos for 45mm gauge and all are quoted as having a 1.2m minimum radius curve.........

If you fit good side control on the lead truck and make the 1st and 3rd axles the ones with flangless wheels, an eight coupled loco would go around a sharper curve than one with the flangless wheels on the 2nd and 3rd axles. However the side control needs to be right and it wouldn't hurt to fit wider tyres on the leading flangless wheels.

You've asked this question before I think. The only way you'll find out for sure is to build some sort of dummy chassis out of bits and pieces lying around and try it. A couple of bogies screwed rigidly to a block of wood at the right spacing, with the inner wheels removed, will soon tell you if it will work or not.

Regards,
Graeme

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests