Locomotive Coal (hence lo-coal) wagons, not to be confused with the similar wooden sided Bogie Coal Wagons (Bocoals).
All-Steel Open Bogie wagons (ex-RAF Fauld) built by, or to a design, of Robert Hudson Ltd, Leeds, and having two steel drop doors on either side, removable top end bulkhead and a handbrake working on the bottom end bogie. Used as part of the Permanent Way Department and S & T department works trains. Numbered 74-80 and 81.
All have RAF type pin and link couplings, hook and link coupling of these vehicles is not possible without the use of a 4-wheel RAF wagon fitted with an adaptor buffer. This must be used to couple with all 'chopper coupling' fitted locos. Only Harlech Castle, Harold and some of the small Simplex locos can couple directly.
From 'A Traveller's Guide' (Blue Cover early 2000s)
"Though the loco is barely visible, it is in fact 'Moelwyn'. The only time I've seen such a train on the FR in 40 years! The various wagons in use may be interesting, though not easy to identify."