loco class??

[Elag66]

is this a class25??

[GeraldH]

It's a Class 31

[Elag66]

It's a Class 31

Thanks

[SRman]

Class 30. They became class 31 when re-engined with English Electric prime movers, although all were re-engined before they could carry the class 30 numbers under TOPS.

As built, they had Mirrlees engines of various horsepowers fitted, mostly in the type 2 power range, a few in the type 3 range, and just one uprated to 2000hp in the type 4 range. The EE engines (now class 31) all had a 1470hp rating, remaining as type 2.

[Mike Parkes]

The new engines were fitted 1964-1969 so a number of 31s ran in green and over a third had been re-engined before the first rail blue 31 appeared and even then a large number were re-engined without being repainted - the principal visual change being that the exhaust ports on the roof were rotated ninety degrees from the original parallel to the roof edge to being at right angles.

[stuartp]

For practical purposes (like looking for a model of one) it's a 31. If you want to be really pedantic, if the photo was taken before 1972/3 (when TOPS became a thing on BR) then it's a Brush Type 2.

They're all the same loco for RTR modelling purposes.