Bachmann Presflo Cement Wagons
The first 'Presflo' appeared in 1953 and those that followed were for the bulk handling of cement. Many batches were made by or for British Railways between 1955 and 1964. During this time, several variations crept in, some of which Bachmann have included in their tooling. Some 'Presflos' were modified for salt traffic and later slate powder traffic and eventually carried fly-ash.
In 1960, Associated Portland Cement ordered their own fleet of 'Presflos' from
Butterley Engineering and Metro-Cammell Ltd. These were to the same design as the BR
wagons. They were initially painted yellow but, to hide the cement deposits, they were
repainted in grey. Tunnel Cement was another company that ordered a batch of their own
wagons, as well as hiring from BR. They were loaded through two top hatches and unloaded
under pressure and the strengthening of the sides for this gave them their strange
appearance. They were replaced from 1984 onwards and all had gone by 1991. 
These are very detailed models. Bachmann have included variations in their tooling which include either one vacuum cylinder (20T) or two (22T). Other differences will be found in buffers, brake levers and vacuum discharge pipes. The Bulk Tunnel Cement wagon is a 20 ton vehicle and numbered B888112 (38-260A), while the Blue Circle Cement wagon is one of the 22 ton vehicles and carries the number B888723 (38-270A).