An update ref my original post #1 about 37181 (above). Others are also looking in to this as a favour to me (so thank you), but I am now as certain as I can be, that on the date concerned (5 March 77) this was a railtour originating/ending Paddington, possibly one of the LNER society trips that I and others used back then, but for which there seems very few records or details have survived.
SixBellsJunction / Railgenarchive / RCTS Railway Observers for March, April and May of that year, are unable to assist, although one observation on the Railgen site* did confirm my thoughts about the Railtour theory, as per below.
As such if any of the following rings any bells with anyone, please feel free to let us know, thanks;
The primary destination on 5-3-77 was Barry scrapyard for a dose of redundant steam (it was my first visit so many cops, especially non SR types, the latter I may well have seen some of in the 1965-67 period but the old man didn't make notes at the time, lol !)
Given the destination, it seems odd (if I were on a service train) that at Reading I observed the 08.15 Paddington-Cardiff (Reading 08.49) come and go with 47.508* (Railgenarchive), and then remained at Reading to observe and note a further 2 x 3 car DMMU's, 1 x cl. 31, 2 x cl. 50 and 2 x HST's, before noting 47.145 with a suffix of 'hauled by'. Hence my Railtour theory.
It is my belief this tour with 47.145, headed direct to Cardiff and Barry Island, where all decamped for a wander around Dai Woodhams yard. My own photo's confirm the presence of quite a few people in the yard such as myself.
This is where (I believe) 37.181 was attached to the rear of the train, and hauled us back towards Cardiff, turning left via Ninian Park and Bridgend**, then leaving the main line and running via Jersey Marine North Jn (Swansea avoiding line in effect) and then turning North via Hendy Junction and Pontardulais towards Craven Arms and Shrewsbury.
At Shrewsbury it would appear that 47.448 replaced 37.181, and took us via Wolverhampton, New St, and (most likely?) Leamington Spa and back to Reading and Paddington?
A long shot again, but if this should ring any bells, particularly with those who (like me) obviously had an interest in seeing the steam in Barry scrapyard, then any comments welcome!
Thanks
** Edited: other notes I made at this point on the day, suggest the train I was on, went around the back of Canton depot, as opposed to running direct from Barry to Bridgend.