On a Treherbert-Cardiff service. Note the very young child up a signal post which was the last remains of the line into Ynys-feio colliery (ceased production c1930), just south of Treherbert station.

Perhaps that's the cameraman's youngster " up the pole " , and I trust he got down again in one piece from his lofty perch !
5618 has a white disc in place on the bufferbeam which those who understand these things will probably confirm identifies the working for signalmen along the line , and which is more usually seen on freight duties , but she's in typical Welsh scenery here , and are those coal slurry mounds in the backgound or a more natural feature, I wonder .
Equally well suited to branch line passenger duties within the many Welsh valley lines as well as hauling heavily loaded coal trains the little " 5600 's " were designed with just such duties in mind by Mr. Collett in 1924 , a time when many of the earlier classes taken into G.W.R. stock from the former Welsh railway companies were no longer suitable for overhaul at Swindon and a replacement design was urgently needed.
The inside cylinder block with its valve covers shows up well in this picture , a feature copied and adopted from many of the earlier pre grouping classes , and necessary to enable workings on narrow branch lines as outside cylinders would have limited use of the class on such duties .