The Adams Radial Tanks

Simple query please folks; why were they so named?
I was once told "It's because there are no straight edges on them, only curves". Another person suggested "All the curved lines are radii of the same circle".

Anyone know the definitive answer please?

 

Hi, I run the website for Thorncombe Railway Activities Club.

http://sites.google.com/site/traclubsite/

Thorncombe is a very small village in deepest Dorset, not too far from Lyme Regis. I have been looking for a photo (jpg) which shows an Adams Radial Tank at work on the Lyme Regis branch. The closest I have is one I took myself when 30582 ran a special through Woking.

http://nick301.photos.us.com/p39252646.html

Does anyone have a jpg of one at work on the Lyme Regis branch which I can use on our website? If so, please email it to the address on the link.

Many thanks, Nick

PS: new members and visitors to the club are welcome.

 

A Bissell or Pony Truck has a pivot pin and a frame that is attached to that pivot pin. The wheelsets run in axleboxes that are part of that framework and when the wheelsets are displaced they and the truck rotate horizontally about this pivot pin. With a Radial truck, there is no pivot pin. However, the axleboxes are situated in curved guides so that, when the wheels are displaced sideways, the wheelsets rotate horizontally about a theoretical pivot point. Radial trucks are quite common (eg 56XX and LNER Pacifics with the Cartazzi variant) but for some reason, the Adams 4-4-2T's and the L & YR 2-4-2T's seem to have been singled out with the term radial in their commonly referred class names.

 

The 'Brighton' 0-6-2Ts were known collectivly as 'Radial' tanks I think...