Notes
Coupled wheels are 15 spoke 5ft 2" diameter, with the crankpin between spokes (Slaters 7862NW).
The trailing wheels are 10 spoke, 3ft 9" (Slaters 7845).
Screw link couplings and motor/gearbox of your choice also need to be sourced
These locomotives, a tank version of the Cauliflower, were designed by F W Webb and introduced in 1898. They had all the latest Webb refinements of the time, steel buffer beams, fluted coupling rods, metal brake blocks and were fitted with carriage heating equipment. Coal rails were fitted from 1902, making them the first LNWR tank locos to be so fitted.

The first 70 of the class were fitted with piston valves, the final 10 having slide valves when built. The piston valve locomotives were progressively converted to slide valves, the whole class having been modified by 1920. The locos weighed 52 tons in working order and were the largest LNWR tank locomotives until the introduction of Whale�s 4 4 2T Precursor tank engines in 1906.

The driving wheels were 5ft 2��diameter, 15 spoke with 24"crank throw and the trailing wheels were 3ft 9" 10 spoke. The cylinders were 18" diameter with a 24" stroke, boiler pressure was 150 lb per square inch.

The Watford Tanks were introduced primarily to haul the 50ft suburban coaches recently introduced on the Euston to Watford service. They were also used extensively on other suburban style routes such as the Birmingham Walsall and Manchester Buxton services. All, bar three, of the class passed into LMS ownership, with 15 lasting into British Rail days, the last being scrapped in 1953. By then, they were dispersed all over the network, however none were further south than Birmingham.

On the London to Watford service, they averaged 230 miles per day, starting and stopping approximately 100 times. They possessed very brisk acceleration, and were reputed to be capable of over 70 miles per hour, and as such were a strong testament to the design and engineering of Webb�s simple locomotives.

In LNWR days the numbers were scattered around, the LMS renumbered them in the range 6860 � 6936. BR allocated the survivors numbers in the range 46876 � 46931, but only two locomotives carried their BR numbers, 46900 & 46912.

In LNWR days the Watford Tanks were always painted black, with grey, cream and red lining. The black used was known as �drop black� which gained the name �Blackberry Black� due to the effect of careful application and cleaning resulting in a blackberry hue. Lining was applied to the tank and bunker sides, the splashers, the cab sides above the tanks, and the rear of the bunker. Please refer to a photograph or one of the �reference� books available to ensure that you apply the lining as per prototype. The grey was always outside the red by 1 5/8 inches (1mm will do on the model!). Generally the grey line was 5 ins. from the edges of panels, except for the cab sides, where it was 3 1/2 inches away.

Both front and rear buffer beams were painted red, while the buffer bodies were black. The interior of the cab was Indian Red with the insides of the splashers and the boiler back head black. The frames were painted black inside and out in LNWR days, although the LMS later painted the insides red.

In LMS days not a lot changed and very few received LMS red, they were mainly black both with an unlined livery prevailing.

Only two of the class actually carried their allotted BR numbers, of these at least 46900 carried the early BR emblem.