2-6-4 Tank engine question

QUOTE (neil_s_wood @ 13 Mar 2007, 07:53) <{POST_SNAPBACK}>It took me ages to spot any difference in them and as I know nothing about tank locos wondered what the difference was.

Where you looking at them with your eyes shut

As has already been pointed out,-the top one is a B.R. Standard 4MT,whilst the bottom one is a Fairburn..
The B.R. design was a development of the earlier Fairburn one for the L.M.S. [which itself was a development of the earlier Stanier 2-6-4T]
Below the running plate they are very similar,but above,there are several obvious major differences which are easy to spot to aid recognition:-

Running plate;

BR; The running plate is continuous from the front buffer beam to the front of the tanks,including the highly distinctive step up below the smokebox with it's large 'near-vertical' area [a common design feature of the BR Standards..]
LMS; The running plate is split into 2 sections,with no 'vertical' section linking them,and the top part is set lower than that on the BR loco..

Boiler;

BR; Clack valves on first ring behind the chimney..
LMS; Top feed just ahead of the dome.

..and last but by no means least....

Tank/cab/bunker;,

BR; Highly distinctive curve from top to bottom that matches the profile of a BR Mk1 coach,bottom of tank has 2 'steps' whilst the top is flat,cab front spectacles are raked back at an angle.
LMS; Flat sides to tanks and bunker,bottom of tank has 1 'step',and top of tank slopes down at the front.

It's just like those 'spot the difference' competitions that you get in magazines from time to time.....

Thanks for the clarifications. I know it seemed like a dumb question for those who are already familiar with these type of locos but I am not. I have never really looked at tank locos before. I was trying to find a 4MT as I had seen one on a DVD and when looking at that and similar locos found that there were many almost identical ones. I was interested in the differences. I also wanted to clarify if this was the one that I had seen last year at Bo'ness. So thanks again.

That wikipedia item certainly covers it all. Thanks for that!

Neil, something that covers it even better is the "Book of the BR Standards" and the " Book of the BR Standards 2" both by Richard Derry which are available from Trainworld in Melbourne.

Ozzie21

QUOTE (neil_s_wood @ 14 Mar 2007, 13:53) <{POST_SNAPBACK}>That wikipedia item certainly covers it all. Thanks for that!