Stanier '8F' inauguration at Peak Rail

The public debut of the maroon Stanier 8F, 8624, took place on Saturday 23-May-2009, as part of a 3-day steam gala at Peak Rail for the Bank Holiday weekend. The first day didn't quite go to plan, as I'll explain shortly. I was marked as driver on 8624 during Saturday morning with Chris Ward as fireman, then we were both to swap onto 'Royal Pioneer' giving brake van rides at Rowsley for the afternoon.

When I arrived at Darley Dale South Yard, The invariably-smiling Chris was on hand and 8624 was quietly 'brewing-up' at the North End of Siding 2. 'Royal Pioneer' was being prepared in the usual spot, over the inspection pit towards the south end of siding 2. After exchanging greetings with Derek and Harvey on 'Royal Pioneer', I returned to 8624 to set about the driver's preparation duties.

I've talked about preparation of 'Royal Pioneer' in an earlier article. The same principles apply to an '8F' - it's just a bit bigger. The '8F' has one major advantage over 'Royal Pioneer' - it has two outside cylinders and Walschaert's Valve Gear outside, so it's easier to get at most oiling points. Some of the corks are a bit high-up so that the foot-framing (running board) gets in the way but hinged flaps are provided in the foot-framing so that the driver can attend to these oiling points from above.

On 'Royal Pioneer', steam oil is dispensed by a sight feed lubricator but on the '8F' a mechanical lubricator, driven from the motion, distributes oil as long as the engine is in motion. During preparation, the driver has only to lift a hinged lid on the lubricator to ensure there's sufficient oil in the reservoir for the day's work. The driver will also turn the lubricator by hand perhaps twenty turns to 'prime' the oil lines with oil before setting off.

On the '8F', a second mechanical lubricator (a 'Silvertown' of a slightly different pattern) distributes 'motion oil' to the top of the coupled axleboxes to feed the journals and hornguides. At present, there is no manual handle for priming, so this lubricator is 'cranked' by turning the nut on the end of the pump spindle with a spanner.

Although the mechanical lubricator will provide a supply to the axleboxes, it's also necessary to go underneath the engine to attend to the axlebox underkeeps, for Stanier introduced the very reliable Swindon design of axlebox on the L.M.S. The picture below shows one axlebox on the pony truck of the '8F'.

The 'Achilles Heel' of many Derby-built locomotives before Stanier was said to be inadequate bearing size in axleboxes. There was a famous tussle when Derby placed an order with Beyer Peacock in Manchester for the 2-6-0 + 0-6-2 'Garratts'. Beyer Peacock politely pointed out that they would recommend the use of their standard axleboxes with generous dimensions. But Derby insisted on the standard axlebox, with predictable consequences for reliability. On his arrival at Derby, Stanier went about quietly introducing a number of Swindon ideas, including his version of the Swindon axlebox. The underkeep is in the form of a generous oil reservoir. A worsted pad is immersed in the oil, with a spring pressing the pad upwards to wipe oil onto the journal. Each reservoir is topped-up via a protruding pipe closed with a cork, accessible when the locomotive is standing on an inspection pit. The bottom of the reservoir has a hex-headed bolt which may be slackened to drain any water from the reservoir.

When the crew of 'Royal Pioneer' had finished their preparation, they moved the engine off the pit, so that I could set back 8624 onto the pit to check the axleboxes. By the time I'd done this, it was 09:15 - time to tie the two engines together and make out way to Rowsley. Having obtained the Darley Dale - Matlock single line staff from the Darley Dale signalman, the crew of 'Royal Pioneer' were able to operate the South Yard Ground Frame and drag us onto the running line. With the ground frame restored to normal, I received the staff (Peak Rail has changed it rules so that it's now the leading engine which carries the staff) and we made our way towards the Darley Dale Down Home signal which 'cleared' as we approached.

I surrendered the single line staff to the signalman as we entered the double track section through Darley Dale station. As we approached Church Lane, the signal came 'off' and, having picked up the staff for the Church Lane - Rowsley section, we carried on up the bank, to stop by the crossover ground frame on the approach to Rowsley. Here, we 'split' the two engines.

I took 8624 up to the 6-coach train in the platform and 'Royal Pioneer' made its way into the sidings to pick up a brake van for the brake van rides. The guard called us onto the stock and members of the 48624 society joined the train, for the first round trip due to depart at 09:45 was to be be a private working for society members. The Traction and Train Crew Officer had decided to drive the first trip, so I was left at Rowsley, waiting for the train to return.

When the train returned, it was quickly discovered that the big end bearing on the right hand side was very hot. Alen gave a monosyllabic diagnosis - "SHED!". So, I took over a 'sick' engine, unable to work the first revenue-earning public train. 'Royal Pioneer' was told to drop his brake van off and get attached to the front of the train to work the service whilst repairs were attempted to 8624. Once 'Royal Pioneer' had shunted onto the train, I was able to gingerly shunt 8624 across to the shed, where we positioned the engine as required by Alen and the working members of the 48624 Society.

The team took down the right hand motion in order to examine the big end. This is an easier task on an locomotive with outside motion, but it's not a job for the faint-hearted. The parts are heavy and cumbersome and strength is required, even with a willing team. My pictures of 8624 include some shots showing the repair in progress.

Once the four nuts securing the return crank are removed and the eccentric rod is disconnected from the expansion link, the return crank and eccentric rod can be lifted off and set aside. The gudgeon pin is then removed, allowing the little end of the connecting rod to be separated from the crosshead. The big end is then slid off the crankpin and the long, heavy connecting rod withdrawn. This is easier said than done because the connecting rod passes through the motion bracket (also called the 'spectacle') and has to be manhandled towards the cab until it's clear of the motion bracket. The rod can then be set down on wooden blocks to allow the whitemetal bearing to be examined.

Judicious 'scraping' was performed on the whitemetal bearing to remove possible 'high spots'. Years ago, this was a favourite training job for apprentices in the works. Meanwhile, the oil pad was given a good soaking in fresh oil. Before re-assembly, all bearing surfaces were given a liberal application of oil, then the procedure for taking down the motion was reversed until the engine was complete again. As a test, we ran the engine the length of the loco yard and back three times. After each run, the big end temperature was checked and the following run was made at a slightly higher speed. The repair was judged a success and the engine was released to traffic, after less than three hours on shed - a tribute to the 48624 team's professionalism.

While all this was going on, 'Royal Pioneer' had completed two round trips to Matlock. 8624 shunted to the south end of the train and 'Royal Pioneer' moved from the north end to the yard, to resume brake van rides. The first revenue service operated by 8624 was the late-running 13:45 departure, reporting number 2M05. The engine was tender first, of course, going to Matlock. I'm afraid the Stanier 4000 gallon tender doesn't give the driver very good visibility when running tender first. When I used to work mechanical signalboxes (unofficially) when I was young, I was intrigued that some freight train drivers would insist on turning their engines on a nearby triangle so as to work back 'chimney leading', whereas other drivers would save time by working back tender first. Most of the British Rail Standard tenders were 'inset' at the top, to improve visibility.

I've discussed some of the duties of the traincrew in 'The working of trains' but if it's an unfamiliar engine, the driver also has to work out the best way of handling the engine. Below is a small selection of the things to bear in mind
- On any engine with piston valves, aggressive use of the cylinder drain cocks is essential, to prevent condensate being trapped in the cylinders.
- Each time the regulator is shut, there's a fair amount of steam left in the main steam pipe and this steam will be expanded as it passes through the superheater, so the engine will remain under power for some seconds.
- A screw reverser allows fairly precise setting of the cut-off, but it can become a little heavy if you're doing a lot of shunting.

Chris had things well in hand on the fireman's side, as usual, so I could concentrate on driving. It's always policy to start off in full gear, to ensure you can produce enough torque to start away cleanly with a moderate regulator opening. After a few yards, I pulled her back to 55% for better economy. Since 55% is also the marked position for drifting (coasting), I could shut off without making any further adjustment to the reverser. On this run, we wanted to keep the speed down and, every time we stopped at a station, we checked the right hand big end which remained cool. So we enjoyed an uneventful, if rather restrained round trip. I was reminded that this was a fairly special occasion as we approached Rowsley on the way back in bright sunshine. In the field on the left, there was a fan of about ten photographers, lenses trained on our engine as we made our sedate progress into the platform.

On our arrival, I squeezed up and Chris 'hooked off'. Long-term Peak Rail member Bill Berisford marked the occasion by the charming gesture of presenting me with flowers, shown in this picture by Mick Cramp. Then it was time to relieve the crew on 'Royal Pioneer' and Jack and Mike took over 8624 for its second revenue trip. The Traction and Train Crew Officer decided to take 8624's third revenue trip. Chris and I continued the brake van rides during the afternoon and when 8624 completed its third trip (by now about one hour 'down' on the schedule), we coupled the two engines together. 'Royal Pioneer' led the way home to the South Yard at Darley Dale, where the two engines were disposed. An interesting and tiring day. The early failure of 8624 was clearly disappointing but the marvellous way in which the members of the 48624 society rallied round to get the engine back in traffic was in the very best traditions of steam railways.

Other Articles on 8624 in this Blog

Stanier '8F' restored at Peak Rail.
In a Spin with Pete Waterman.

Ask the Expert - 1

"Thank you. This is a rather nice commemorative plaque featuring a Great Western 'Castle' class locomotive. Modelling can be very variable on this sort of objet but this is quite well done. There's a limit, of course, to how much detail can be incorporated but the classic lines of the 'Castle' are quite clear."

"Churchward introduced the Great Western 'Star' class which laid out the basic format for a four cylinder express locomotive. Divided drive, with two inside cylinders set well forward connected to the leading cranked driving axle and two outside cylinders driving the next axle via crankpins. Although Stephenson link motion had been used with complete success on other types, Churchward decided to fit two sets of Walschaert's motion inside the frames working the piston valves on the inside cylinders directly and the piston valves for the outside cylinders via rocking levers. Initially, the 'Atlantic' wheel arrangement (4-4-2) was to be used, as on the De Glehn compounds he'd evaluated, but Churchward became convinced that the extra adhesion contributed by a pair of coupled wheels, rather than a pony truck, would be more valuable, giving rise to the classic Great Western 4-6-0. The 'Castle' closely followed the outline of the earlier 'Star' but Collett did provide a somewhat improved cab, allowing us to quickly identify this plaque as a 'Castle'."

"Turning to the material which has been used for this plaque, the brown colouration suggests terracotta which, in the right hands, can provide the level of detail we see here... I beg your pardon? Chocolate? Did you say CHOCOLATE? You are surely mistaken" ...

(MUNCH) ... "Certainly, it's rather softer than I would have expected. Terracotta requires the correct kiln temperature for 'firing' to produce a durable artefact ..."

(MUNCH) ... "Of course, Churchward used only a low degree of superheat and it wasn't until after the Second World War that higher superheat was used. The traditional Great Western sight feed lubricator was not sufficiently reliable with the resulting higher steam temperatures and so a mechanical lubricator was used for the cylinder oil. A double chimney and blastpipe was introduced, to reduce back pressure and consequent power losses" ...

(MUNCH) ... "The name of Sam Ell is associated with this post-war work at Swindon where the steaming of a number of classes was significantly improved, often by quite minor changes to the draughting. By this time, the work of Lemaitre, Chapelon and Kylala was becoming well known" ...

(MUNCH) ... "Now, looking again at this commemorative plaque ... Oh dear, it seems to have gone. Next object, please!"

Fourth Rail Electrification

Fourth rail electrification, White City, London Underground

Electric railways were introduced towards the end of the 19th century. Electric traction was particularly suitable for use on underground railways where steam traction could be particularly troublesome. Early systems used locally-generated direct current, produced by stationary steam engines.

Largely because of the available materials for generators and motors, working voltages were limited to six or seven hundred volts. At these relatively low voltages, currents are fairly high, so a third rail, the conductor rail, was provided to carry the traction current between the feed point and the train to be powered. One or both running rails were used to return the current to the feed point. The conductor rail was carried on glazed porcelain insulators (invariably called 'pots') mounted on the transverse timbers ('sleepers') to which the running rails were also fixed. The high insulation resistance of the insulators ensured that almost all the current flowing in the conductor rail was that drawn by the train.

The situation was more complex as far as the return current from the train was concerned. The running rails were held at the proper gauge by fixing them rigidly to the sleepers which, in early days, were generally made of wood - a reasonable electrical insulator. To provide resilience against the dynamic loads of passing trains, the sleepers were buried in ballast, often crushed limestone - again a reasonable insulator. Sleepers and ballast were in contact with the mass of the earth. The earth resistance from the running rails may be fairly high in dry conditions but, when wet, earth resistance falls. Although most of the return current would flow from the train to the feed point through the rail, a proportion leaked from rail to sleeper and from sleeper to ballast so that a significant current flowed through the mass of the earth. If there were nearby metallic water or gas pipes, some of this stray current could flow through them, causing damage by electrolytic action.

The situation was even worse in deep tube lines, which were lined with sectional cast iron sections which would not only suffer electrolytic action but, if rings were not bonded together, could display arcing. To mitigate this problem, London's Underground evolved with a 'fourth rail' to carry the return current via a path isolated from earth.

The outer conductor rail is positive at around +420 volts and the inner conductor rail, mounted between the running rails, is negative at around -210 volts. These are the theoretical voltages under dry conditions. Leakage resistance across every porcelain insulator will provide a multitude of paths to earth from both conductor rails which can alter the voltage to earth ratio of the positive and negative conductor rails. To define the 'normal' ratio, London Underground provide bleed resistors every so often connected from each conductor rail to earth. This 'normal' ratio will be subject to significant change on surface lines under varying weather conditions.

Fourth rail electrification with modern concrete slab track

For notes on traction power distribution on London Underground click here.

For an excellent article on conductor rail systems by Russ Elliot click here.

The world's railways use a wide variety of d.c. and a.c. electrification systems employing both conductor rails and overhead conductor systems - to see the Wikipedia article on 'Railway Electrification' click here.

Related posts on this website

All my posts on London Underground can be found here.

Stanier '8F' restored at Peak Rail

During the Second World War, the 'Big Four' railways were still in existence, but under Government direction. Riddles was seconded to the Ministry of Supply to ensure that locomotives were available for the war effort. One of the classes he chose to manufacture was Stanier's '8F' freight locomotive and orders were distributed amongst a number of workshops. This is how the locomotive numbered 48624 post-war came to be manufactured by the Southern Railway at Ashford Locomotive Works. It was delivered in 1943, one of a batch of 13 locomotives built there and was initially allocated to Willesden M.P.D. on the L.M.S.

After a little over 20 years service, the locomotive was scrapped in 1965 as part of the frenzy to eliminate steam and languished in Barry scrapyard until 1981, when a group of enthusiasts purchased the locomotive and commenced restoration at Peak Rail's Buxton site.

The problems Peak Rail experienced at Buxton necessitated a fresh start at Darley Dale and so 48624 relocated to the South Yard at Darley Dale to allow work to continue. The amount of money and dedication necessary to restore any locomotive from Barry condition, particularly a large one like an '8F', is hard to imagine. It took 28 years of hard work by the volunteers of the 48624 Society to bring the locomotive back into steamable condition and in that time some of the stalwarts have passed on. Almost all the work has been carried out in the open air - it's only in the last few months that the locomotive was moved to the new Locomotive Shed at Rowsley, offering a significant improvement in working conditions.

On the 25th April 2009, the locomotive moved under her own steam for the first time in 43 years. Alan Taylor made a video of this historic event. To watch Alan's historic video, Click here.

During the restoration, the locomotive had been painted in British Rail black, numbered '48624' and with the 'star' symbol on the cabside (indicating that the locomotive had improved balancing and was suitable for working high-speed freight trains). But, at a late stage, the controversial decision was made to turn her out with the L.M.S. running number '8624' and L.M.S. express passenger livery which, of course, is historically incorrect. The Power Classification has been altered to '8P', to correspond with the livery.

I imagine there'll be some debate about the appearance of the engine. My view is that people who have expended such a super-human effort in bringing the locomotive back to life have a perfect right to choose the livery. Although I have some personal reservations, it can't be denied that she looks very handsome in the chosen colour scheme and I'm sure the general public (as opposed to the rivet-counters) will approve. Click here for my pictures.

The public debut of the locomotive in revenue service is set for 23rd May 2009 at Peak Rail - click here for the Peak Rail website.