Calder Valley DMUs

A recent thread on the introduction of Pacers turned my mind back to the period just before the 150s started operating the Calder Valley route. I remember the 110s but I have just read an article on www.stormrail.info that states the following:

"In a panic over costs West Yorkshire PTE agreed to some smaller 2 car sets being derated to one engine per car known as class 78's. They could barely stagger up the hill from Bradford but fortunately did not have to tackle Miles Platting bank as they used the Cheetham Hill Loop"

Now I'd have thought that when they scrapped the non-powered centre cars there would have been left with only power twins so where did the unpowered trailers come from? Unless they just ran them with one engine switched off? Also I can find no reference elsewhere to class 78 - surely a locomotive designation?

Edit: just noticed it says 1 engine per car. I still don't understand!

I think some power twins had an engine isolated on each power car so 2 engines instead of 4, but I also have a recollection of some vehicles where the final drive and gearbox were left in mesh to drive the alternator but that might just be a misunderstanding.

From: https://www.railcar.co.uk/type/class-110/operations-later

There was a lot of pressure from the WYPTE to downgrade the power cars to one engine only, as had been trialed on a Class 104 and implemented on the Class 111s. They believed that the effect on timings would have been marginal, but this was resisted as in reality it could have added 20 mins to a Manchester - York journey due to the nature of the line through the Calder Valley.

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Thanks for your replies. I hadn't realised there were 2 engines in each car. They must have been operating to a very tight budget indeed for this to have been thought of, considering that these units were originally specified with plenty of power specifically because of the gradients of the Calder Valley.

I presume the class 78 bit is nonsense and that they were never reclassified to a different TOPS number? (78 or anything else!)

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The 78xxx was just a number series the 'half power' 104/111 sets were renumbered into rather than a reclassification - the only reclassification was their type which was DHBS (rather than DMBS) and DHCL (cather than DMCL), the H being to note half power. During the early 1980s, a lot of DMUs in both the North West and Yorkshire were reduced from 3-car to 2-car and others from 4-car to 3-car to cut costs. Of the 28 Calder Valley (110) sets, 3 trailers were withdrawn around 1982 as unrefurbished, and those 3 sets ran with 101 centre cars for a couple of years. Then the major cull took place in 1983/84, another 15 trailers were withdrawn, and the 3 101 trailers disappeared off to the LMR (to go in Class 120 sets IIRC), which left 18 power-twins and 10 3-car sets.

The "cutting of costs" by removing the trailers was notional only; under the accounting of the time the service was charged by the car-mile, so taking a trailer out reduced costs to 2/3 of what was formerly charged. The actual impact on costs was way less.

There were of course plenty of 2-car units with a driving trailer, and their power car with two engines, which seemed the same approach as two power cars with one engine each.

Built at the Birmingham Rail Carriage and Wagon works between 1960-61 and lasted until 1988 when they were replaced by 150/2's. ( Correct me if I'm wrong)

But it later resulted in the nonsense on the Morecambe-Leeds line of derated three car Calder Valley sets being attached to 101 power twins to give them enough guts to climb the hills

BucksBones said:

I presume the class 78 bit is nonsense and that they were never reclassified to a different TOPS number? (78 or anything else!)

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As an aside I seem to remember Railway Magazine publishing a picture of a suposed class 78. It was in an April edition c.1981ish.

randyrippley said:

But it later resulted in the nonsense on the Morecambe-Leeds line of derated three car Calder Valley sets being attached to 101 power twins to give them enough guts to climb the hills

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The Calder Valley 110 sets were never derated. The class 110 sets kept all of their engines. Some of them had their unpowered centre cars taken out, which actually made them faster. It was the Rolls Royce engines class 111 sets that had an engine taken out of each power car, and a class 104 based in the Manchester area.