Friday 9 July 2010

D8 'Penyghent'

D8, deputising for failed 68013, pauses at Darley Dale with a down train

On 27th June 2010, I was driver on 68013 at Peak Rail which, sadly, became a total failure, as described here. This left me 'spare' and so I helped out in the efforts to provide alternative motive power. Both the Class 31 and the Class 37 were ruled out so it was the Class 44 'Penyghent' which ran the (somewhat delayed) service.

Now, I know I've (perhaps unkindly) referred to people who become too enamoured with diesel traction as 'Turning to the Dark Side' but I've never denied that there's much of interest in modern traction. Compared with the relative simplicity of steam locomotives, diesel locomotives require more complex systems and learning the principles involved can make an absorbing study. It's also true for diesels, as it is for steam, that whilst it's easy to drive badly, it's a lot more difficult to drive well.

So, I was happy to spend most of the day on D8 as a 'Supernumary' sharing Secondman duties.

References

Ian Allen published a useful book by Stephen R. Batty in 1985 called "The Last Years of the 'Peaks'" (ISBN: 0 7110 1493 0). It's mainly photographs but there's some interesting text. The book is still available on the secondhand market.

On the Web, Wikipedia is a good first stop.
There's an excellent history with lots of pictures here.
One the same site, the Sulzer diesel engine has its own history here.

My small collection of pictures of D8 are here.

The Best Laid Schemes ...

On 27th June 2010, I was marked as driver on the six-coupled 'Austerity' at Peak Rail. This locomotive has received a 'makeover' recently, being transformed from WD150 'Royal Pioneer' in green livery (a historically correct identity) into '68013' in black livery with British Railways transfers. Although she looks handsome in black, this locomotive was never taken into British Railways stock so this is an 'assumed identity'.

In another development, after years of stabling locomotives in the South Yard at Darley Dale, the Locomotive Department has finally moved to the new engine shed at Rowsley.

Derek the fireman and Colin the cleaner had matters well in hand when I arrived so I was able to concentrate on oiling round and the daily examination of the locomotive. I've described these duties before in 'Driving Turn at Peak Rail', although this description was based on preparation at Darley Dale, rather than Rowsley. The standard oiling diagram for this class of locomotive is shown below but, of course, the work is carried out from memory of what's required.

Standard Oiling Diagram for 'Austerity' 0-6-0T

Oiling round gives the driver an opportunity to get 'up close and personal' studying all parts of the mechanism. There's a collection of pictures showing this class of locomotive in detail here.

Previously, when we stabled at Darley Dale, it was an easy matter to start the day with Driving Experience courses using the line between Darley Dale (South Yard) and Matlock Riverside. Now we stable at Rowsley, we still use the Darley Dale - Matlock section of line for the Driving Experience courses, but it's necessary to first 'position' the locomotive from Rowsley to Darley Dale. This is currently done under an 'Engineering Possession' as signalmen do not book on until later in the morning. The single line staff for the Church Lane to Rowsley section is issued to the driver by the person-in-charge, allowing the locomotive to make its way to Church Lane. The person-in-charge opens the level crossing gates, calls the light engine over the crossing and collects the single line staff. The locomotive is then authorised to travel to Darley Dale Station on the double-track section.

On the 27th June, Rob was the person-in-charge and we made our way bunker-first to Church Lane and were loosed through the crossing at Church Lane without incident. I decided to stop at the motor-operated points at the entrance to the double-track section, since the move had been authorised by handsignal, rather than a fixed signal with the benefit of point detection. I shut the regulator and applied the steam brake.

Not a lot happened.

There was some retardation, so the brake blocks had clearly come on, but the insistent 'chuff-chuff-chuff' from the chimney indicated that the regulator had not closed. I checked the regulator handle, opening and closing it firmly without effect. I considered whether the regulator valve had become 'gagged' in second valve, but that didn't seem a likely explanation (for a little more information on how the regulator is arranged, see 'Locomotive Regulators'). Next, I swung on the pole reverser to 'link-up', sometimes hard to do once the regulator is open and steam is flowing. 'Linking-up' (or 'Notching-up') cuts the steam off earlier in the piston's stroke, reducing the torque at the wheels and giving the brakes a better chance of taking effect. A combination of linking up and actually getting the pole into opposite gear for a while allowed me to bring the locomotive to a stand, wreathed in steam escaping from the open drain cocks.

I decided to see what happened with the reverser in 'Forward'. As soon as the brake was released, the locomotive started to move and I used the "apply brake and swing on the reverser" technique to stop. Once I was satisfied we could stop, I put the engine in back gear, released the brake and carried on to Darley Dale platform where our antics were being observed by Stationmaster Ian, our driving trainee and Rob.

We agreed to make an attempt to get the engine on 'main valve' and then close it but the response seemed to confirm that we were not controlling the actual valve with the handle. By removing the regulator handle and attempting to turn the rectangular section of the regulator rod with an adjustable spanner, we reduced the flow of steam a little, but we did not regain control of the regulator valve.

Of course, trying to diagnose a problem on a regulator is harder because the valve itself is usually inside the boiler and completely inaccessible. You just have to imagine what's going on from a knowledge of the construction. The 'Black Book' (the locomen's 'bible' published by British Railways as a training manual) shows the following diagram of a typical dome-mounted slide valve regulator.

Illustration of a typical dome-mounted vertical slide-valve regulator

With reluctance, the engine was declared a complete failure and apologies were made to our driving trainee. A number of 'phone calls ensued to advise management of the problem. I agreed that I could move the locomotive to the pit in Darley Dale yard, where we would dispose and wait for Rob to bring a diesel shunter which would move the failed engine back to Rowsley for attention. Meanwhile, management were seeking a 'scratch' diesel crew who could operate a diesel passenger service. Since Derek had been nominated for secondman duties, once we'd moved our engine to the Darley Dale pit, Derek made his way back to Rowsley to assist and I disposed.

A little later, Rob appeared with the diesel shunter, attached my 'dead' engine and propelled it to Rowsley, stabling it on the pit outside the shed to cool down. By this time, the boiler pressure was down to about 20 p.s.i. It was clear that the steam dome would have to be opened but it would be some hours before this could be achieved so I went to see if I could help with getting the diesel service instituted.

When I returned in the afternoon, Paul and Rob had removed the dome cover and the bolted-on inspection cover, to reveal the inside of the boiler and the regulator but it was still very hot in there!

The open dome giving (limited) access to the Regulator Valve

The problem had been confirmed. Moving the regulator handle in the cab turns the regulator rod, turning a crank fixed to the regulator rod. This crank moves the regulator valve via a link attached by turned steel pins to the crank and the valve. The two turned steel pins should be held in position by split pins. Although the upper split pin was in place, connecting the link to the valve, the lower split pin was missing, allowing the turned steel pin to become displaced and the link to become detached from the crank on the regulator rod.

View of regulator valve, showing 'U' shaped pilot valve in front of the broad main valve.

View of linkage

It's the first time I've had to 'fail' an engine for a defective regulator. I do know of two problems with the regulator which happened to other drivers in preservation - in one case the handle fell off and in the other case it broke off!