the EE type 4s

By 1959 BRB had been happily recieving their orders for various type 4 DE power, all at this point with the 1Co-Co1 bogie arrangement. This prove to be a major fly in the ointment for the locos, adding both wieght and some mechanical issues. This would in the parallel universe seal the fate at productiion of 119 D200s and 205 LDA variant "peaks"

EE had already made it's own rather competent if ponderous d200 obsolete in terms of express passenger work, and in heavy freight. It was the deltics, and the CSVT v12 engine which spelled the early cessation of the original order for over 300of the type 4s. In 1960 EE offered BRB an upgrade to the fleet order of d319-d343 which were as good as in production, certaily as far as ration dictacted procurement and parts planning wiht sub contractors was concerned. The locos had already been modified under a change control to the then favoured split head code boxes. The further modification was as follows- the fitting of aircharged cooling, stainless piston rings, new d6700 style exhaust manifolds and a major alteration to the electrical circuits. ETH was also offered as standard. Control and automatic overload correction/prevention were also modified more in line with type 3 orders for home and foreign markets.

Whilst the power unit was rated at 2350hp @850rpm, the main electrical circuits gained a fourth field diversion, or rather had a complete change in the staging with an additional one to boot. This allowed the locomotives to lay down higher ampage for starting trains and to give better performance at the other end above 80mph. Diversion is activated at approximately 16, 35, 60 and 75 mph depending on rate of fall of ampage, with maximum ampage for which ever field at about 5% below that speed. Thus the d3xx's became known for their slogging like ability to start heavy trains, often around 1000tonnes. THe max'trac'effort was estimated at 69000lbs at 14mph, but some enthusaist recordings showed them perhaps as high as 75000 when recovering failed trains, tus having the claim as highest effort for that time in 1961.

It all rendered them most useful for these heavy friedt duties when progress above 16mph could be predicted...a desirable situation because they had a tendency to overheat- the slab plate bogies not assisting heat dissapation as much as an open format 'commonwealth' frame based bogie. On lighter trains of 200-500 tonnes it meant progress was far from pedestrian, and really inseperable from their more powerful successors the Dp2s.

In accepting the design iomprovement at the time in 1960, BRB allowed a pause in which 8 split code D200s were delivered with only the electrical modifications. The expensive engine components wer not fully fitted eg the whole aire char inercooling system. however the rest of the modified split boxes were ordered along with the final change control for the last 14 D200s which had split boxes, dual heating and dual braking from new in 1962-3. As mentioned elsewhere, the remaining 40 or so orders were diverted into Dp2 production units.

A further variant did however arise- really just the EE type 3 with the v16 CSVT at 2350hp. These were seen as being a potential frieght variant of the Dp2 wiht a lighter overall weight than their big sisters and less complicated three divert control. 32 examples were built at RSW Derby , being diversions away from the main type three fleet at the time. These were all allocatd to south wales to bolster the type 3s there and avoid the need for double heading on some trains over 600 t. They worked later from toton, immingham and grangemouth providing oil and pertrochemical deliveries due to their power and very high reliability. However, deemed non standard in reveiw of the early seventies, 1974 all examples were sold to austrailian frieght haulage Ltd with the alteration to engines being two large turbos at either end and gear driven cam system. Two such PUs were retro- fitted to the two newest "d300s" and kept them in departmental use at least until 1995.

As mentioned 8 d319-d327 had been delivered wiht only electrical and some enigne mod's. These were temporarily uprated to 2230hp by 1) increasing fuel and turbo pressure 2) adding a notch 9 which allowed the engine to rev to 1000rpm. Reliability was noticeably affected by this temporary attempt to make up towards at least an even performance between all new D300s. In 1964 the last example had been upgraded although it was alleged that D323 had an output higher than all the others at maybe 2500hp. We will never know because in 1966 it was destoyed by glancing crash with a derailed Brush t4 and burned beyond economical repair due to the resulting fuel explosion.

The rest of the order was then diverted into the Dp2 fleet, of which the first 50 locomotives have much electro-mechanically in common before the later utilisation of the KV10 load governor on the further v16 orders.