0-6-0 Locos

[52D]

Can anyone give a good reason why comparitively modern J39s were scrapped and the old guard in the shape of J27s in the North East and J36/37s in Scotland soldiered on till the end of steam.

[Andrew Craig-Bennett]

Some of the last steam locomotives to be withdrawn in East Anglia were the last four J15s, one of which is now on the NNR. The J15 was a truly ancient looking engine.

[buckjumper]

Can anyone give a good reason why comparitively modern J39s were scrapped and the old guard in the shape of J27s in the North East and J36/37s in Scotland soldiered on till the end of steam.

Simple: the J39s were a troublesome class.

Their maintenance costs were high; they had hot axlebox problems which were never solved, and until late in life frequently wrecked their own motion. After an unsuccessful design alteration which made matters worse, a solution was discovered, however, it made for very labour intensive repairs.

The pre-group examples you've quoted were cheaper and easier to maintain.

[52D]

Thanks for that bit of info, i must apologise to the contributor above you regarding J15s i forgot to put them in with the others.
It will be good to see the J21 in steam alongside its J15 brother. I hope there is a chance to see both engines in action at the GCR passing each other with lengthy coal trains and pulling in a certain contributors words(Stainmore forever)a replica of stainmore trains with one of them detaching and running light over Swithland viaduct.

[Andrew Craig-Bennett]

One thing about the J15 and the J21 is that their running gear is truly massive, with heroically oversized components, by the lights of whatever horsepower the boiler, steamchests, valves and cylinders might conceivably achieve. Worsdell certainly did not expect anything to break!

[paullad1984]

stainmoire forever indeed

[Greedy Boards]

The recent MREMAG Poll highlighted yet again, that an LNER 0-6-0 is required by many of us. Yet apart from the popularity of the J15, all of the other locomotives of this category only scored up to 40 or so votes.

I think that any LNER 0-6-0 would be most welcome, and would happily buy a J15, if one is produced, to operate as a branch pick-up. However, as a North Easterner, I would suggest that our own LNER Encyclopedia info on such locomotives, indicates that a J26/J27 (as they were identical externally), could be used in Great Eastern territory as far south as Cambridge, and as far north in Northern British territory as Edinburgh.

The J26/J27 has the potential for being operated on many lines, both within and external to the North Eastern Region, and we have a preserved example currently awaiting a long overdue overhaul - Could this be the next in line, once we get the J15 steamed up

[russ]

and J36/37s in Scotland soldiered on till the end of steam.

One point not mentioned so far is that the early diesels intended to replace steam particularly the NBL's (21/29) and Claytons (17) had legendary unreliability

[pete2hogs]

I wonder if someone can explain why the J38's were apparently reliable and lasted until the end of steam in Scotland, but the J39's - virtually identical - were considered such a liability?

[paullad1984]

perhaps the larger wheels meant they were used at speeds that the j38;s werent? seem to remember reading somewhere there was a history of valve gear dissintegrating at speed?

[pete2hogs]

Hmm. They were only 6" larger, but maybe it was just enough to change the kind of duties they were used on?

[buckjumper]

seem to remember reading somewhere there was a history of valve gear dissintegrating at speed?

I've already alluded to the two issues with the J39s, so here's a bit more meat on the bones.

In his autobiography Bill Harvey details the very frequent problem of the locos wrecking their motion. The cause was quite simple: the castle nut securing the gudgeon pin would loosen, shear it's split pin and work off. The gudgeon pin then worked out, fouled the valve rocker and broke it's brackets.

The first design alteration was to reverse the position of the nut from the outside to the inside slide block which made it more accessible. However this made matters worse as the pin still worked out, but now fouled the leading hornblock, bending and fetching down the slidebars.

The eventual solution, not effected until after the war was to do away with the nut fastening by making the hole in the slide blocks of less diameter than in the small-end bush. The drawback was that it meant the whole assembly had to be lifted into position in one piece, sliding it in between the slidebars from the rear - very labour intensive at a time the railways were haemorrhaging skilled labour, maintenance standards were generally in decline and severely in arrears.

Harvey mentions that the J39 motion was the same type as fitted to the GC Director class (which had 6'9" wheels and ran considerably faster than the J39s), yet doesn't recall a single example of a gudgeon pin working lose on one of those locos, despite it being a 'frequent occurrence' on the J39s.

The other major problem with the J39s is detailed on this site's page on the class - they were subject to hot axleboxes on the right hand side due to severe twisting forces exerted on them. It is interesting that the J38s don't appear to have been affected to the same degree - perhaps the larger wheels intensified the twisting force? Yes the Director's had even larger wheels, but I believe were considerably less powerful. I'm afraid we're in the territory of speculation as neither Gresley, Thompson nor those on the front line such as Harvey were able to resolve the issue and despite various modifications over the years a solution was never found and the increasingly high maintenance costs of this 'problem class' were ultimately their undoing and heralded their swift demise.

[pete2hogs]

Thanks for the detailed info.

You've got to admit the difference in reputation between the Directors/J38's on the one hand and the J39's on the other is pretty fascinating - quite a mystery. And with such a large class it really is quite amazing that no concerted effort seems to have gone into solving the problems. But that does seem to be an unfortunate habit of the LNER which we otherwise love

It just shows the pitfalls of engineering design - the J39 was all tried and tested features, just some unfortunate combination of factors seems to have made them react together in an unfortunate way.

A couple of questions occur to me -

Did areas other then the GE regularly use the J39's on passenger traffic?

Would there actually have been a different crank throw between the J38's and J39's?

The K3's also got withdrawn en mass, and the L1's. Both decisions a bit enigmatic also, perhaps slightly less so with the L1's (not popular, passenger traffic going diesel or electric). But the V2's didn't, nor the v1/3's.

[hq1hitchin]

Yes, a bit of a mystery why the LNER built so many J39s and yet they always seemed to have a reputation for shaking themselves to bits at speed.

Not that they had a monopoly in that respect, the Hitchin L1s were known as 'Concrete Mixers' and were alleged to posess an ufortunate habit of dropping their motion. A pity, because they were fine looking machines and one set of local heroes once even got as far as Brighton with a L1!

[buckjumper]

Would there actually have been a different crank throw between the J38's and J39's?

Apologies - reference removed. That was a relic from a draft which shouldn't have made the final copy as I couldn't find the relevant data.