GWR 51XX CLASS LOCOMOTIVE KIT
BRIEF HISTORICAL DETAILS
The engines which form the basis of this kit were an up-to-date version of the Churchward engines introduced in 1903. They are divided into two classes the 51O1 class (51O1-511O, 515O-99, 41OO-79) introduced in 1929, for general use, with 200 lb. pressure boilers followed by the 61OO class (61OO-69), specifically to work accelerated London suburban services, with 225 lb. pressure boilers. 

For a detailed history of this numerous class, Part Nine of The Locomotives of the Great Western Railway published by the RCTS is essential reading. 
Other valuable sources of information and photographs are: 
A Pictorial Record of Great Western Engines Vol. Two - J.H.Russell - OPC 
Churchward Locomotives - Brian Haresnape & Alec Swain - Ian Allan 
Locomotives Illustrated No. 33 - Ian Allan 
Great Western Railway Journal No.5 (Winter 1993) - Wild Swan. 

VARIATIONS POSSIBLE WITH THE KIT 
Water Fillers.  Numbers 5101-10, 5150-89, 6100-6109 were fitted with a screw down lid whereas the remaining engines were fitted with a lever type. 

Cab shutters.  Numbers 5190-99, 6110-69 & 4100-79 were fitted with shutters from new. The earlier engines received shutters from 1933 onwards.  

ATC equipment.  Fitted when new to 5160-99, 6130-69 & 4100-79 and applied to the earlier engines between 1930 and 1933. The earlier engines had the ATC conduit pipe clipped midway up the valance on the left hand side whilst the later engines had the pipe clipped under the lower edge of the valance. The earlier engines were fitted with the standard ATC shoe bolted to the front buffer beam and clearly visible in photographs. Later engines, including all the 61XX series, had a less visible shoe mounted beneath the pony truck. 

Journal lubricators mounted on the tank top. The majority of the 51XX & 61XX series were so fitted when built. The 41XX series did not have these lubricators and some of the earlier engines subsequently had them removed.

Step on tank front.  Numbers 5101-10, 5150-89, 6100-6109 were fitted with a step of traditional appearance. The later engines had a step of the same design as fitted to the rear of the bunker. 

Upper front lamp bracket.  Moved to smokebox door on a few engines. 

Spare lamp brackets.  On early engines these were mounted towards the footplate edge along side the splasher whilst later they were placed further forward and in front of the splasher. 

Whistle shields.  Fitted to 4160-79 when new and later to a few of the earlier engines. 

Handrails on tank strap.  Two extra handrails were added on the strap over the boiler from circa 1945 onwards. 

Bunker steps.  The welding of three steps to the left side of the bunker began in 1952. This necessitated the shortening of the handrail on the bunker side whilst at the same time two extra handrails were added one to the rear of the cab cut-out and one on the cab roof.
 

VARIATIONS NOT POSSIBLE WITH THE KIT
Safety valve bonnets.  Numbers 5101-5110 & 5150-59 were fitted with tall safety valve bonnets. The safety valve bonnet supplied is of the short type fitted to the remaining engines. 

Bunkers.  Numbers 5101-5110 came out with a recessed fender above the flat bunker top, whilst Nos. 5150 onwards had the upper half of the bunker extension recessed to match the fender. The kit only caters for the recessed bunker and fender. Several of the earlier engines were subsequently retro fitted with the recessed bunker and fender. 

Trip gear.  The 61XX series worked over the electrified lines in the London area and all were fitted with trip gear for automatic brake application in case of over-running an adverse signal. The A.T.C. apparatus on these engines is arranged to clip up automatically on entering an electrified section.