Sunday 18 December 2016

May the (brake) force be with us...

Since the last update the loco has been in steam and tests carried out on the overhauled brake and the new boiler blowdown system. Both appear to work well. The Westinghouse carriage warming valve was also tested and appears to work satisfactorily. With the tests complete and the tender tyres looking as if they wont be in the UK before Christmas it was time to drain the boiler and make sure that all the steam piping was free of residual water. We have already had some very cold weather at Aviemore during the last few weeks and its important to take frost precautions.

It's worth saying that the steam brake now makes a significant contribution to stopping the loco - even at relatively low steam pressure. This is something new. In the years that the loco has been operated in preservation the tender brakes have done most of the stopping. It looks like this will have changed considerably when we couple loco and tender together again in 2017...

One job that is being progressed is the refitting of the loco brake crossbeam safety chains. These are intended to protect the loco from potential derailment in event of a brake hanger failure. This is something that must have been a hazard in the 19th Century up until steel manufacturing reached a high level of reliability. One of many interesting features of 828 is that she benefited from the great improvements in materials technology that took place in the 1890s. This meant that where locomotives built only a few years earlier relied heavily on wrought iron and cast iron the 812 Class got the benefit of steel for highly stressed parts. Thus the brake hangers on 828 are steel forgings where a few years earlier they would have been made from less strong wrought iron. This means that the likelihood of a failure is much reduced and so the safety chains became redundant. With time in hand it seems worthwhile refitting them as they are part of the original loco. 

I mentioned that the loco had been in steam. This is correct but she was very reluctant to come into steam because the boiler tubes have become sooted up after several steamings without enough exhaust blast to sweep the tubes clean. The consequence of this is that the tubes resist the flow of hot gas and smoke and force it to come out of the firedoor. At the same time the fire burns very sluggishly due to lack of air and the time taken to generate steam increases enormously. The cure is to sweep the tubes with a tube brush - not the most pleasant job with the fire already burning. While I was doing this help came from Alan French who reminded me that a few years ago he had made an 'air amplifier' to stimulate a draft up the chimney of our locomotives as an aid to raising steam. The device was located in the steam store and Alan quickly sorted it out and fitted it. This made all the difference and the fire responded very well indeed. Those familiar with the external blowers fitted to model steam locos for steam raising purposes will be able to picture the principle. The AF Air Amplifier however has no moving parts to go wrong - a marvellous device..!

This will probably be the last post of 2016 so very best wishes to all readers of the Blog and supporters of CR 828 for a very Merry Christmas and a Happy New Year - and let's hope that the Blog changes focus in early 2017 to 828 in operation...!!

A view of the cab showing the boiler blowdown pipe sweeping round the firedoor flameplate and disappearing under the cab to enter the ashpan..

Outside Aviemore Shed, a rather sulky 828 making it difficult to raise steam..

At last, the fire getting some air and starting to burn properly..

Two engines in steam in the early winter darkness..

All testing complete and the boiler cooled down - time to drain it down...

Boiler Empty......just in case...!

One of the two remaining lengths of brake crossbeam safety chain. The crossbeam has a 3/4" hole in it to take an eyebolt. The brake hanger and the brake block are both clearly visible.

117 years of wear - this is what happens when a hard chain link bears against a soft anchor link for more than a century..

Likewise the chain wears on itself over a long time...

Cutting 1/2" plate for new anchor links with the slowest mechanical hacksaw in captivity...but it's still easier than sawing it by hand..!

Making up the new anchor links that bolt to the loco frame plates..

Eyebolt in place with new anchor link attached to frames and new chain getting measured..

Picture taken for a modeller who requested detail of the lettering on the tender

Ditto as above...the correct font and shading as used by the Caledonian Railway Company..

Monday 28 November 2016

Back Braking....

The activity during the last week has mainly been on the loco steam brake. With the assistance of Tommy MacDonald, Calum Titley and Roddie McRae the very heavy and awkward brake assembly was lifted back into place and bolted up. The linkages were then reconnected and adjusted. The new grease lubrication points were charged with grease. We will hopefully now have a steam brake that contributes a bit more to the stopping power of the loco than at any time since her British Railways days..

With the brake completed I was able to have a look at a couple of steam leaks in the cab. These have been attended to and will be checked out when we next steam the loco.

Colin Vaughan is starting to press Rileys for news on the replacement tender tyre forgings which are now becoming overdue relative to the six week delivery lead time that was quoted when they were ordered...

The heavy lifting squad - Tommy MacDonald, Calum Titley and Roddie McRae relaxing after getting the loco brake cylinder back into place under the dragbox..

To help take the weight of the brake cylinder (approx 200 kg) we used the ubiquitous blue rope - a turn around the trailing axle and then over a convenient bar placed across the cab leanouts made quite a difference..

The steam brake cylinder fully back in place and all pipework reconnected and ready for a steam test...

The brakes adjusted....

The loco waits behind closed doors on one of these beautiful cold and very sunny late Autumn days in Strathspey..

Waiting in the shadows.....

Something that I hope we'll see again in 2017... CR828 and 46512 on a special double headed working for the benefit of the Strathspey Railway members and supporters..

Saturday 19 November 2016

Taking a brake...

 It's been a busy time with 828 since the last update on the blog. We've had her in steam twice to check out various repairs and also had the Trustees of the CR828 Trust, the legal owners of the loco, at Aviemore for their AGM. Not all of the Trustees could make the journey to the far North and those who did expressed their satisfaction with the work that has been carried out on the loco. At the AGM Ian Stanworth, SRA Chairman, was elected as a Trustee. The SRA has been very consistent over many years in providing financial support to 828 and it seems fitting that the SRA Chairman should be a Trustee. 

John Greig has been making and fitting more new and improved worsted trimmings to the motion parts - he has made them to give an increased rate of oil flow to ensure adequate lubrication for the new bearings on the big ends and eccentrics. Once the loco is run-in the flow can be reduced.

The oak planks donated by the National Trust for Scotland courtesy of Aidan Bell at Inverewe Gardens have been marked out and cut roughly to size as the new wooden packing for the front buffers. Final machining is being undertaken by a neighbour of Keith Holyland in Auldearn. The finished spacers will be fitted shortly.

Some time was spent recently adjusting the loco brakes. It can be fairly said that the loco steam brakes have never contributed a great deal to the stopping power of the engine. The tender steam brake has always seemed to provide most of the brake power. I discussed this several years back with the late William Peaston who had driven members of the 812 Class in BR days when he was a Driver at Greenock Ladyburn Shed. His recollection was that the steam-braked locos were better 'stoppers' than the Westinghouse air braked versions. He was therefore surprised that we found 828 to be a poor 'stopper'. We may have uncovered the reason for this. BR removed the Westinghouse air brakes from 828 in the mid-1950s and fitted the steam brake that we have today. When the loco was steamed last week it was partly to test the brake following adjustment. The result was disappointing; there was a great deal of leakage past the brake piston and the brakes were very slow to release. A decision was therefore taken to remove the brake cylinder from under the dragbox and strip it for a full examination. This revealed that one of the two piston rings was too tight in the cylinder due to lack of ring gap clearance. The gap was adjusted and the piston, which had been very difficult to move, became a very good sliding fit in the cylinder. We also found that the bellcrank lever that transmits the force from the brake piston to the brake pull rods had seized on its pivot pin and required excessive force to make it move. With something of a struggle the pin was freed and the bellcrank removed. With everything cleaned up we decided to fit grease injection points to the bushings to prevent this problem recurring. The Caley had provided an oil hole in the bellcrank but this was found plugged with coal dust and no oil had penetrated to the pin for a long time..

Colin Vaughan has been pressing Rileys for an update on delivery of the correctly sized tender tyres. As before, the order has to be placed via West Coast Railway Company Ltd. Rileys have been pressing them for an update but none is available thus far. Hopefully we will hear something before the end of November..

Looking smart outside the Shed and getting ready for another steam test on 11th November..

In flight...! Nathan Lightowler demonstrates 828 in action for the CR828 Trustees at their AGM on 12th November..

CR828 Trust Chairman, Jim Spy climbs aboard the Trust's loco on 12th November. Some other guy gets into the picture too..

John Greig fitting new trimmings to the RH Big End on 11th November..

Roddie McRae with a wheelbarrow load of oak planks and one of the old spacers for the front buffers..

Marking out for cutting the oak to size..

Roddie McRae putting a coat of paint on the new LH Driving Hornblock..

The loco steam brake cylinder - bolted to the underside of the dragbox. Because of the geometry of the brake pull rods the piston moves upwards to apply the brakes. This is a reversal of the practice adopted by the LMS and BR where the brake piston pushes downwards to apply the brakes..

It's a heavy lump...! Roddie McRae removes the nuts while Colin Vaughan and Calum Titley take the weight of the cylinder..

Safely landed on the Shed floor we can see the piston peeping coyly out of the cylinder and very reluctant to move..

Colin Vaughan admires the upturned cylinder...

Piston stripped for inspection on the bench in the Shed fitting shop..

Reassembled with both piston rings now having the same gap clearance when fitted in the cylinder

Colin Vaughan applying some heat to help remove the brake bellcrank pivot pin..

The pivot pin driven almost completely out...

The refurbished brake cylinder awaiting refitting to the loco..

Brake piston rod top-end rebushed by Nathan Lightowler..

Tapping out the bellcrank for a grease nipple to assure correct lubrication of the pivot pin.

Job done - grease nipples fitted to the bellcrank and the brake piston rod pin..

Under the loco drilling and tapping the bellcrank hanger bushes for grease nipples..

With the bellcrank removed the hangers (riveted to the loco frames) lie on either side of the brake rigging pull rod. At the top of the picture is the trailing axle and forward of it is the rear of the ashpan..

Bellcrank back in place and lubrication assured...

Low sunlight on a very cold Autumn day (18th November) catches 828 as she watches 46512 outside in the Shed yard getting ready for a test run....

Sunday 30 October 2016

Maybe Next Month....

The waiting continues but the work hasn't stopped. While we wait for the replacement tyres to arrive with Ian Riley there is an opportunity to get on with other work on the loco and the tender.

On the tender we've been able to refit the brake hangers and fit new brake blocks. This should have been a very straightforward job. Where it became awkward was when we found that the new brake block castings didn't quite fit the hangers. The blocks have a clevis cast into them into which the hanger should slide and then the securing pin pushed through and locked with a split pin. Bob Edwards, the man from the RPSI, drilled the pin holes through the new blocks and we set about fitting the first one and that was when we found the problem. The solution adopted was to remove all six hangers and skim them by about 0.060" in the milling machine. This should have been pretty straightforward but the Caley (or the LMS) chose to make the hangers from a very hard grade of steel. Using Nathan Lightowler's best cutting head and a lot of new tips we finally managed to get a fit for all of the hangers and the new brake blocks are all safely fitted...

On the loco we took the opportunity to strip the old paint off of the smokebox and the chimney so that they can be repainted with high temperature gloss black. This was done using a needlegun. The chimney needed some filling to recover the elegant curve of the Macintosh design. The end result looks very nice particularly after the smokebox door was repainted.

The smokebox door closure mechanism has not looked completely satisfactory for some time so we decided to try and improve it. The problem lay in the tendency for the locking screw to droop below the boiler centreline and give a rather untidy appearance when viewed from the side of the loco. Correcting this involved some remedial work on the "dart" that pulls the door tight against the internal crossbar inside the smokebox. An improved guide tube was made and fitted and the overall result looks much better.

We hope that the replacement set of tyres will be with Ian Riley before the end of November....

Tender brake block correctly fitted to the RH Leading brake hanger..

Bob Edwards and Nathan Lightowler finding out just how hard is the steel used by the CR for their tender brake hangers. Even Nathan's biggest and best multi-tipped milling cutter struggled to do its job..

Fitting the new springs to the centre axle was easier than renewing the brake blocks...

The smokebox and chimney minus their old paint (the chimney cap didn't need the old paint removed)

Filling the imperfections in the chimney casing and the doorplate rivets..

Rubbing down the filler...

The chimney ready for painting...

Partly painted chimney...

Roddie McRae painting the inside of the smokebox wingplates..

Alan Murphy painting the fallplate (piano lid) that covers the cylinder and steamchest front covers..

Smokebox painting completed but the door lock removed for maintenance..

The "dart" receiving attention..

Job done...! Painting completed and the door lock back in place complete with the famous Caley star..!