That was a Class 37, a "Type 3" locomotive for fast or heavy freight and secondary express working produced by the English Electric company in 1960.
It was supposed to be the UK-wide standard Type 3 engine but the Southern Region, being constitutionally inclined to be different, decided to use these instead:
Manufactured by BRCW, the Class 33 was a very different sort of engine.
While the 37 was a "Co-Co" (it had six axles, each of which was powered), the 33 was a "Bo-Bo" -- with four powered axles.
It managed this trick by dispensing with a boiler for heating carriages -- the Southern was moving fast to an all-electric heating system.
Carriage heating boilers were immensely heavy, so dispensing with it saved enough weight to lose two of the axles -- which, in turn, meant the bogies (another immensely heavy component) could be much lighter. The 37 weighed roughly 100 tons, the 33 in the high 70s.
The 37s had a slightly higher top speed, which helped in some of the faster regions, and, eventually, it penetrated the Southern, too - it was such a handy machine that it couldn't be spurned and, of critical importance, each axle on the 37 carried less weight than the 33: the 37 was the ultimate "go anywhere" engine, no matter how weak the track.
As a study in two engineering approaches to the same problem they make for a fascinating comparison.
The aesthetic approach alone is worth a book: the 37s were styled to follow contemporary North American practice while the 33s were a development of a standard style adopted by the British Transport Commission which was trying to introduce a more consistent approach to design across all of British Railways.
Which you prefer is a matter of taste or, perhaps, familiarity. As an Eastern Region boy I grew up with 37s (the first few models off the production line were set to work on express passenger turns on the old Great Eastern lines). But I wouldn't say no to a 33, either. Does that make me a tart?
4 comments:
Please allow me to add some info regarding heating boilers.
For the german V200.0 (comparable to the WR D800 Warships) the heating boiler had a net weight of roughly 2 tons (for its stronger sidekick V200.1 the net weight was reduced to 1,5 tons to compensate for the power and weight increase). As with the steam locomotive it is the water 'reservoir': 4 tons for the V200.0 and 3,6 tons for the V200.1 (again to save weight). So the weight sums up to about 6 tons.
Thanks -- a geek like me loves that sort of detailed information!
I think the reduction in boiler/water-tank weight was sufficient for them then to shift to a Bo (4-wheel/2-axle) bogie rather than the Co (6-wheel/3-axle) used on the 37s -- and that, in turn, saved tons more weight.
There's no doubt the 33 was a nifty design; but I also find it intriguing that it ended up with a higher axle weight than the 37 and so was actually less useful, despite being so much lighter.
On the weekend i bought a copy of MLI issue 184 about the class 33. A reasoning is suggested why the Southern Region did go for the BoBo. The civil engineer (of the Southern Region? my question) demmed the BoBo as Go Anywhere nearly on the entire network (again Southern?), whereas the CoCo would be heavily restricted (despite the lower axle load).
The same reasoning is behind the decision of the Swiss, German and Austrian railways to abandon CoCos in new designs now for some 30 years in favour of modern BoBos with radar-controlled tracion motors with antiskid device. The long three axle bogies are distorting the track in tight radii, it is said. No new CoCos also for France and Italy state railways (using BoBoBos instead), at least for Italy due to the same reasoning.
Another reason (for the Southern Region) was the assumed usage of EMUs for passenger work if i understood correctly.
Oh and i was misunderstanding your comment. The class 33 did indeed have a ETH (i assumed it didn't had any heating system at all).
Britain is still committed to Co-Co locos -- but for heavy freight (both the Class 66 and the brand-new Class 70 are Co-Cos). The one high-speed diesel Bo-Bo freight design, the Class 67, was a bit of a disaster, the axles pounding on the track causing appalling damage.
But generally for faster locos, Bo-Bo is now the order of the day -- the Class 90, the last electric mixed-traffic design from British Rail (which is still used for fast freight and for the heaviest passenger trains of all, the Anglo-Scottish sleepers), is a Bo-Bo as indeed are the HST and the Class 91, the last electric express passenger locomotive design.
Today for passenger equipment Britain is obsessed with distributed traction rather than locomotive power: as the rest of Europe reduces powered axles, we seem to be multiplying them.
Interestingly, the Class 37s have survived longer than the 33s. They've also been exported across much of Europe where they've found work hauling engineering trains on the construction of high-speed lines (in France, Italy and Spain). And they're still operating engineering trains in Britain.
Notwithstanding the idea of Co-Co axles splaying track (something I've not come across before though I can see the theory), 37s were used over 33s on weak track, the lower axle loading reducing the stresses. They were used extensively on, for example, the Highland lines, before those were ceded to DMUs.
And now I'm rambling on...
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