class 43 weight

[truckman060473]

noticed the spec. plate on the side last week at 70 tons (approx). they used to be 76t didn't they? an MTU engine can't be 6 tons lighter than a Valenta! it's lost the weight somewhere though.

 

[Murph]

noticed the spec. plate on the side last week at 70 tons (approx). they used to be 76t didn't they? an MTU engine can't be 6 tons lighter than a Valenta! it's lost the weight somewhere though.

Remember that the re-engine is possibly closer to a re-build. AFAIK, pretty much all of the heavy components were replaced - engine, generator, turbos, cooler groups, control gear, etc. Also remember that the Valenta, the Napier turbos (where a big chunk of that lovely scream comes from), and all the other major equipment is 1960s engineering (with a small hint of very early 1970s), so modern materials and engineering techniques can achieve pretty major weight savings.

For example, computer-aided stress analysis, thermal analysis, fluid dynamics etc, has allowed engineering margins to progressively drop back significantly closer to 100%, without necessarily sacrificing reliability or safety. Prior to modern techniques, and without wishing to in any way belittle the great achievements of our historical engineers, there was a significant element of making it 150-200% stronger than needed (just pulling numbers out of the air here to illustrate the point - skilled engineers would know the correct margins of over-engineering to use for each scenario, as well as where there had been problems in the past). They would then observe full scale prototypes under prolonged and torturous running to determine if stress, thermal, and lubrication issues were properly addressed (this last part should still be done today, but the computer analysis pre-prototype allows much more to be done at that stage).

I wouldn't like to claim that the above did actually result in a 10% (roughly) weight saving, or that they definitely used to be 76t, but it does seem within the realms of possibility. Also, just for clarity (and possible confusion), was it 76 tonnes (modern, metric), 76 short tons (US imperial, 2000lbs/t, ~907kg/t), or 76 long tons (UK imperial, 2240lbs/t, ~1016kg/t)? It comes from an era when the standard UK measurement would have been the long ton (AFAIK - I don't think metric had been heavily adopted at that time).

 

[No Fault Found]

Re-engine was just that, pretty much engine only. Oh and the new headlight panel. Same cooler group, same alternator, same compressor etc.

 

[Murph]

Re-engine was just that, pretty much engine only. Oh and the new headlight panel. Same cooler group, same alternator, same compressor etc.

Oh, I stand surprised and corrected. I could have sworn that I read somewhere (a good while ago, so no hope of remembering where I read it) that essentially the entire mechanical compartment(s) were being fully refitted.

 

[Techniquest]

Re-engine was just that, pretty much engine only. Oh and the new headlight panel. Same cooler group, same alternator, same compressor etc.

Technically the cooler groups have changed too, pretty sure the Marston and Voith lot have gone for standard Brush coolers throughout now. Turbos I'm sure have also changed, although I can't for the life of me think what they are. GNER did a lot more work when they sent their lot in for MTU'ing, more than FGW did at least (with exception to 053 and 056 IIRC).

 

[43034 The Black Horse]

Technically the cooler groups have changed too, pretty sure the Marston and Voith lot have gone for standard Brush coolers throughout now. Turbos I'm sure have also changed, although I can't for the life of me think what they are. GNER did a lot more work when they sent their lot in for MTU'ing, more than FGW did at least (with exception to 053 and 056 IIRC).

Same with EMT. New electronics cubicle and new WSP system. EMT were first (and only!) TOC to have tried and tested Brush Coolers in Paxman's VP185.

As you say, Techniquest, cooler groups have changed. Marston, not to mention the odd Serck cooler (43079 last to carry one) have all gone over to Voith. Also correct in saying 053/6 are the only GW PCs to have the new WSP and Electronics cubicle and WSP. Turbos have changed from SA-084s and NA-256s to some new(-ish!) fangled thing....
(I don't sign that much on the Valenta, but far far less on MTU!)

 

[royaloak]

The engine and all direct ancillaries, turbos etc were changed as a complete package, the control circuits were altered to work with the new engine, the cooler groups were also changed.
The Alternators are still the same, they were never much of a problem anyway and of course it means that all the traction electrics remain the same.
The new engine is lighter even though it is a V16 as opposed to a V12 of the Valenta and VP185, but 6 ton(ne)s seems a bit much although with the rest of the heavy stuff (cooler group etc) I suppose it is possible.

 

[Techniquest]

With regards to the weight, they've been 70t since I first got into the scene in 2003, so when were they supposed to have been 76t?

Slight loss of weight may have come about when the guards' accommodation in the power cars was removed, but otherwise I can't think of anything to change drastically the weight.

Scott: Ta, had forgotten about the Serck coolers. If memory serves they weren't that widely used on the Western were they?

Pass on what the turbos in the fleet are these days, can't say I've cared to look it up!

 

[No Fault Found]

Technically the cooler groups have changed too, pretty sure the Marston and Voith lot have gone for standard Brush coolers throughout now. Turbos I'm sure have also changed, although I can't for the life of me think what they are. GNER did a lot more work when they sent their lot in for MTU'ing, more than FGW did at least (with exception to 053 and 056 IIRC).

FGW cooler groups are all Voith. I also classed the turbo as part of the engine, they are MTU blowers.

 

[kestrel]

Always were 70ton, dunno where the 76ton came from unless you're looking at the weight of the prototypes?

 

[truckman060473]

hmm. you appear to be right Kestrel. my old 2000 locomotives book says 70t too. is there a possibility that mid 80's class 43's were 76t then because I cant think why i would come up with this figure unless i'd seen it on one at some stage. when i was a kid Carmarthen station loco trains were usually class 33, 37, 47 and the HST, and the crompton is closest here at 77/78 ton so i'm not sure. could it be the metric / imperial "ton" measurement that is the answer here?

 

[asylumxl]

Not an imperial/metric conversion, as the imperial measurement of 76 tons would mean the metric tons is 77.2 tons.