Just for fun, I tried to find out what the last steam engine built was for each of the major railway works. So far, I've found out the following:
Ashford: 8674, LMS Stanier 8F
Brighton: 80154, BR Standard Class 4 2-6-4T
Crewe: 92250, BR Standard Class 9F
Darlington: 78064, BR Standard Class 2 2-6-0
Derby: 73154, BR Standard Class 5 4-6-0
Doncaster: 76114, BR Standard Class 4 2-6-0
Eastleigh: ?
Gorton: 61349, LNER Thompson B1
Horwich: ?
Stratford: ?, GER N7
Swindon: 92220, BR Standard Class 9F
As I said, this started as a bit of fun, so I'm certain I've missed a few works sites.