Class 17 reliability

[Strathclyder]

Was it not the crankcases rather than the heads?

You may be correct, I couldn't remember.

The Paxman History site has a paragraph on the crankcase issues with the ZH engines:

The engines initially supplied to British Railways were of aluminium alloy construction. Cracking of the castings became a major problem and the engines were rebuilt by Paxman with cast-iron crankcases at great cost to the Company. John Cove, who worked for Paxman at the time, has told me that British Railways had previously tested the first pair of engines with aluminium crankcases before placing an order for a quantity. By that time Paxman had had some experiences with aluminium castings on the YHA and possibly also the YGA aircooled engine. Both types had experienced troubles with threads and failures in cast aluminium. John went on to say: "Consequently we suggested to BR that we supply the engines with cast iron crankcases from the start but BR were quite adamant that they wanted the engines to be exactly the same as the ones they had tested and which had given no trouble. We were so keen to get the order that we failed to stand up for what we believed was necessary and so supplied them in aluminium. But before long these engines in service had run longer hours than the test engines and troubles began to become apparent and we had to change all the crankcases to iron. The troubles then ceased but this would have been unnecessary if we had taken a stronger line before the order was placed."

The 'first pair of engines' part is most likely referring to the experimental DMU Derby Works outshopped in 1956 (put together using converted ex-LMS coaches and bogies from withdrawn Euston-Watford EMUs) to trial the ZH; these lasted until December 1957 after which Paxman asked that their equipment be returned. Railcar link with more info below:

Paxman Diesel-Electric

 

[delt1c]

I remember at Bathgate seeing the 178.s on freights , only a few years old , yet the exhaust obliterating the area , worse than any steam they replaced

 

[matchmaker]

The Paxman History site has a paragraph on the crankcase issues with the ZH engines:



The 'first pair of engines' part is most likely referring to the experimental DMU Derby Works outshopped in 1956 (put together using converted ex-LMS coaches and bogies from withdrawn Euston-Watford EMUs) to trial the ZH; these lasted until December 1957 after which Paxman asked that their equipment be returned. Railcar link with more info below:

Paxman Diesel-Electric

That's what I was thinking of! Thanks.

 

[Bevan Price]

As a side thought, assuming class 17s replaced steam, am I right in assuming that a total failure of a steam engine was less common, that they would just get slower/less powerful, but still complete the journey where as a diesel failure tends to be a total failure.

Failures of mechanical components were fairly uncommon, but not unknown. A more common cause of failure was leakage of steam - often due to poor design or wear inside valves. The other cause - particularly in later years was failure to produce enough steam due to poor quality coal. Clinker built up in the firebox, restricting flow of air to the fire, and/or ash deposits built up in the smokebox and/or boiler. Sometimes there was enough steam to proceed at low speed; sometimes the train had to stop or "a blowup" (i.e. wait whilst it raised more steam), at other times it might need to wait for assistance.

As for Class 17s, I recall that many went into store, particularly around Derby, when they were almost new. Their other problem was that most of the work for which they were intended "disappeared" as a consequence of the Marples / Beeching policies, and the more reliable Class 20s were kept for what work remained.

 

[Samantha H]

Failures of mechanical components were fairly uncommon, but not unknown. A more common cause of failure was leakage of steam - often due to poor design or wear inside valves. The other cause - particularly in later years was failure to produce enough steam due to poor quality coal. Clinker built up in the firebox, restricting flow of air to the fire, and/or ash deposits built up in the smokebox and/or boiler. Sometimes there was enough steam to proceed at low speed; sometimes the train had to stop or "a blowup" (i.e. wait whilst it raised more steam), at other times it might need to wait for assistance.

As for Class 17s, I recall that many went into store, particularly around Derby, when they were almost new. Their other problem was that most of the work for which they were intended "disappeared" as a consequence of the Marples / Beeching policies, and the more reliable Class 20s were kept for what work remained.

Indeed the work did somewhat dry up and change around the time, coal output from the mines nationally was down about 50 million tonnes over the decade 1960-70 alone. Given their allocation to central belt sheds in Scotland this alone will have seen quite a downturn just in this one aspect of freight traffic given the coal fields in the area, yet to go looking for NCB area specific statistics but it's on the to do list for the weekend.

 

[norbitonflyer]

the more reliable Class 20s were kept for what work remained.

After beeching there was so little work for Type 1s that many, if not most, of the Class 20s were generally used in pairs, where their single cab was not a problem for visibility. Claytons often worked double headed too, but such a lash-up was very complicated: four separate engines (although at least that increased the chances of some of them not breaking down.....)

 

[Merle Haggard]

Failures of mechanical components were fairly uncommon, but not unknown. A more common cause of failure was leakage of steam - often due to poor design or wear inside valves. The other cause - particularly in later years was failure to produce enough steam due to poor quality coal. Clinker built up in the firebox, restricting flow of air to the fire, and/or ash deposits built up in the smokebox and/or boiler. Sometimes there was enough steam to proceed at low speed; sometimes the train had to stop or "a blowup" (i.e. wait whilst it raised more steam), at other times it might need to wait for assistance.

As for Class 17s, I recall that many went into store, particularly around Derby, when they were almost new. Their other problem was that most of the work for which they were intended "disappeared" as a consequence of the Marples / Beeching policies, and the more reliable Class 20s were kept for what work remained.

Most of the ones stored around Derby were in primer, so as delivered from the factories - presumably there was no storage space there.
I was there; they were every spotter's nightmare! Lines of grey locos with NO NUMBERS ON THEM.
The R.C.T.S. suggested recording the works numbers from the builder's plates and reconciling later. Didn't think of that...

After beeching there was so little work for Type 1s that many, if not most, of the Class 20s were generally used in pairs, where their single cab was not a problem for visibility. Claytons often worked double headed too, but such a lash-up was very complicated: four separate engines (although at least that increased the chances of some of them not breaking down.....)

On a 'Freedom of Scotland' ticket in 1968 Claytons seemed to always go out in pairs. It's triggered a distant memory that when they started away you could hear each engine separately going to full revs.

As an aside, I worked in freight movements when the Clayton was moved from Scottish Region to Hemelite. The notice showed a Pomade driver as driving all the way - with route conductors, obviously. By the time he'd made his way from Hemel to Euston and back to Glasgow he must have been well into overtime. Wonder if he was on mileage bonus.

 

[Big Jumby 74]

As an aside, I worked in freight movements when the Clayton was moved from Scottish Region to Hemelite.

Only for the loco to get home sick and make a break for the North sometime later, ending at Clitheroe....