Steam v Diesel Loco overhauls

Now, in the good old days a steam loco got its identity from the frames.

When a loco went into works for a heavy overhaul what you got back was the frames and everything else - could have come from other locos - not even necessarily from the same class.

But what happened with a diesel? I know - for example that the engines were a 'repair by replacement' item and presumably that means the generator as well but what about the rest of it?

 

That's an enthusiast myth not borne out by the facts ...

Tom

 

In reality, what came out of the works bearing the number of the steam loco which went in varied very widely. Crewe and Horwich generally tried to keep together as much of the original loco as possible, and component parts were stencilled with its number to ensure return to correct loco. So to this day some preserved locos still have parts fitted from new. If you look along 6201's handrails, for instance, they bulge outwards at the point where they pass the delivery pipes to the top feed. Originally these were external to the boiler cladding so the bulge was needed. They were made internal in the 1930s, but the original handrails survive.

Alternatively, frame defects amongst Black Fives were sufficiently numerous for Crewe to assemble a new set of frames complete with cylinders. Should a Five with such serious frame defects that they would delay production enter the works, these would be substituted and the original set repaired later, then go into stores for use on the next errant Black Five. At least one preserved Five is not on its original frames.

St Rollox seems to have taken a different view, and what came out could be a curious mismatch of anything as and when it became available.

The LNER seems to have had a different system and, from what I've read, frames replacement was specified at a certain mileage or date. The A1 involved on the bad collision at Castlecary was still standing complete when the 'repaired' engine re-entered traffic.

 

I agree with LMS2968, 45110 is one I was told years ago by Tony Pirie that she has Ivatt frames, the comparison with 5000 was remarkable it was rough riding, 45110 ran like a coach.

 

Frame exchanges only took place on the locos with 1" thick frames, i.e. 5000-5461. Records show that 5110 received the frames from 5375 in July 1950. In December 1956 these were swapped for frames from 5297.
Not all the locos in this number series swapped frames.

 

On the subject of a loco's identity being carried by the frames:

Here's Drummond M7 30667, seemingly near the end of its days:



(Source: http://www.railuk.info/gallery/notes/getimage.php?id=717)

And here it is a bit later:



Close inspection of the frames is revealing, notably how it magically changes from a short frame M7 to a long-frame, push-pull fitted variant of the class, while retaining its original number. (Note the position of the air tank behind the front buffer beam, which required a long-frame loco to fit).

The frames came from long-frame 30128; both locos entered Eastleigh in March 1961, and 30128 was scrapped, but its frames (and who knows which other components) lived on under 30667 . 30031 and 30106 did likewise in January 1961, with short frame 30031 re-emerging as a long frame loco but carrying its original number, and long frame 30106 being scrapped.

30133 received the frames from 30047 and 30378 received those from 30050 at around etc same time, but as those were long frame to long frame swaps, the subterfuge was less obvious.

Tom

 

Tom,

My knowledge of Southern locos is largely confined to the fact that their numbers start with a '3' but isn't there an air tank behind the front buffer beam in both photos?

 

Looking more closely, I think you might be right. The frame swap certainly happened though. Seems that both 667 and 31 were not the photographers friend in their earlier days, though the build records are pretty clear that they were built as short frame locos and the photo evidence shows they ended up having grown up a bit at the front end...

Tom

 

As long as the main frame or bodywork was true a Diesel loco was repaired with normally refurbished components in that class's float of spares from everything from engine down to drivers brake valves. For example Eastleigh overhauled Hastings engines and Generators and sent them to St Leonards inside special transport wagons for fitting and got high hours engines for overhaul back. Even Cabs and cab frames were also replaced if required after bumps. Having a float of equipment very much continues today, you do not want todays trains OOS waiting for engines, compressors etc to be overhauled, the trains need to come on depot in the evening and get replacements overnight so the train is back in service the next day.
This is not new or confined to Railways, Aircraft and Ships operate on the same principal ( A US WW2 T2 tanker had at least three hulls in its lifetime.)


Brian

 

Ah......... Puts pedant head on. Large numbers of T2's (Turbo electric Fleet Oilers) were built during WW2. After WW2, for various reasons - primarily the sheer numbers of them and concerns about the strength of the hulls, the aft sections - which contained the expensive bits - machinery stern frame & propeller were grafted onto new fore sections. I seem to remember this happening as late as the 1970's.

While with modern engines, re-engining ships is becoming more common, generally the original plant will remain in the ship for life.

 

Didn't London Transport do something similar with buses? they had a float of both bodies and chassis and the two were separated for overhaul and when finished,. a body would be fitted to any available, newly overhauled chassis

 

Yes, this also meant the number of vehicles taxed was always less than the number of chassis in the fleet. RM29, for example, went for overhaul in 1963 and did not officially emerge until 1978.