This would probably get a better response, being a question, if it were to be posted in the prototype Questions section of the forum. I suggest that you post there accordingly

Mod4, Thanks for your comment, and, whilst being a modeller since 1967 and seeing said loco on the trials at Desborough, Northants in 1948, I am new to this computing lark and learning every day so please excuse me for my ignorance..

The forum you require is right here, simply click on the blue link!

http://www.rmweb.co.uk/community/index.php?/forum/72-uk-prototype-questions/

There are two books about the exchanges, Written by Cecil J Allen, and published by Ian Allen, the titles are: "The Locomotive Exchanges 1870-1948" and "New Light On The Locomotive Exchanges".

Cheers devondynosoar thanks for that.

Thankyou so much Graham, I really appreciate your kindness for the time taken by you,I'm picturing myself there on June 23rd 1948 (Midland mainline DESBOROUGH Northants) in my short trousers seeing that wonderful MALACHITE machine go through which gave me a lifetime interest in the SOUTHERN RAILWAY!!!!!!