Prieser make a range of figures in 00 scale. That's the same as 1/76 which should work for a 72nd train.
cs.finescale.com/.../162776.aspx
I had a flick through and not sure if many will be suitable for the train your doing. But this set is for a steam train.
www.gaugemaster.com/item_details.asp
As for where to get them, no idea on your side of the pond, they are not easy to find.
I am a Norfolk man and i glory in being so
On the bench: Airfix 1/72nd Harrier GR.3/Fujimi 1/72nd Ju 87D-3