Wanted
 

I would like to operate class 37, 55 and class 59 loco´s in MSTS does any of you know wich add-on´s I can buy in order to get these loco´s

If you go to the following web site(http://www.uktrainsim.com/index.php) you may find what you are looking for.

try London to Brighton add pack. several diesels on there doing goods work passenger specials and shunting