In the '60s Bury St Edmunds had an 03 for shunting the yard (only they weren't 03s then). Like the J69 (68497 I think) which they replaced they did trip workings via the main line to the sugar beet factory and the like. Unlike the J69 which was serviced at the then extant shed, every month or so the 03 would disappear off to Cambridge to be replaced by another 03 half-an-hour or so later. That would last a month when it, too, would swap over. And so on, etc, etc, etc.
Chris Turnbull