Under Pressure

More good progress in the past week. The boiler hydraulic test was completed to the satisfaction of the SRC Insurance Company Inspector and a date in mid-June agreed for him to come back to inspect the boiler in steam (hooray!). Completion of the test allowed us to start refitting various mountings to the boiler and for the first time in a few months 828 now has her safety valves and the elegant and beautiful Caledonian whistle refitted. The combination blower & sanding valve has also been refitted in the cab.

Top machinist Nathan Lightowler has done a great job on the new horn clip for the LH Driving Hornblock and we carried out a trial fit. It fits exactly as it should - a light driving fit. Before long it will be permanently in place and the driving axle suspension springs can be refitted.

The valve eccentrics with their straps are booked to cross the Irish Sea early during the week commencing 30th May and our colleagues at the RPSI are eager to get on with machining them.

A start has been made on assembling the gauge glass cocks after Colin Vaughan arranged a lightning-fast delivery of the correct soft packing. (Most of our gauge glasses have Klinger proprietary packings in them.......but not CR828 - she has a more old-fashioned system of packing. 

The test gauge used for the boiler hydraulic test - 270psi or 18.61Bar in new money...

Regulating the boiler pressure against the input from the Shed high pressure pump. Engineering Director Brian Thomson was standing by the pump unit while I sat on top of the boiler operating the bleed valve...

Safety Valves and Whistle refitted

The swarf produced while drilling the spring hanger pin holes in the new hornclip

The hornclip trial-fitted and it is a beautiful fit...

After the trial fitting the clip had to be removed to form the square holes for the stud that bolts the clip to the hornblock...a matter of some heavy filing..

One square hole...

Two square holes....job done..!

Tyred and Emotional

A week of good progress..! Colin Vaughan called in the Inspection company used by the SRC to carry out NDT (Non Destructive Testing) on 828's wheels and axles to ensure that they remain fit for further service. This is something that has to be done every ten years. The objective is to use a range of techniques to check for any cracking in axles and wheel spokes. Reassuringly the Inspector found that all axles and wheels on the loco and tender remain in excellent condition and the next inspection will be due in 2026...

We carried out an "in-house" hydraulic test on the boiler to check for any problems ahead of inviting the Boiler Inspector to witness a formal test. The test is carried out at the boiler working pressure (180psi) x 1.5 = 270psi. With the boiler pumped full of cold water at 270psi Colin carried out a thorough check in the firebox and the smokebox as well as externally and we were very pleased with the outcome. The Boiler Inspector has been booked to come in and witness a repeat test during week commencing 23rd May. Assuming that this is successful we can move forward to the next stage which is to prepare the boiler for an inspection in steam...!

During the week we removed all six of the tender wheel tyres. This work was largely carried out by Calum Titley and involved a lot of very careful and skilful use of oxy-acetylene burning gear. The tyres are shrunk onto the wheel centres and then locked in position using Gibson Rings. This gives a very secure attachment but is difficult to undo and it took some perseverance to work out the best method of removing the Gibson Rings. Once we had established a suitable method it was then reasonably straightforward to apply it to all six wheels. The wheel centres are old but in pretty good condition. We found evidence of an older method of tyre attachments that predates the Gibson Ring method - this relied on a shrink fit plus the fitting of rivets through tyre and wheel centre. In one case there are a couple of cracks on the surface of the wheel centre along the line of the redundant rivet hole. Ian Riley's firm, who will fit the new tyres, have confirmed that they can make the necessary repairs.

The valve eccentric straps have been reassembled and are ready to be transported with the eccentric sheaves to Northern Ireland for machining. This should happen in the next week or so.

Roddie McCrae has done great job in cleaning up all six of the tender axleboxes and making sure that the oiler pads are clean with fresh oil in the sumps.

The tender axleboxes after cleaning and filling with fresh oil. The oiler pads can be seen in position with the tails of the trimmings dipping into the oil sump. The Caley made their tender axleboxes a generous size...

Checking for cracks in wheel spokes...

Eddy Current crack testing the tender wheels..

Calum Titley making a start on removal of the first tender tyre..

Cutting through the tyre to expose the wheel centre...

First section of tyre removed....

First tyre successfully removed..

Getting more practised now.....tyre removed with only a single cut...

Master of the art of tyre removal....Calum shows how it's done..!

Our ever increasing pile of scrap tender tyres...

In Calum's absence, an amateur takes over - watched carefully by John Greig...!

Colin Vaughan making it look very easy to drive the Shed JCB..

The scrap pile is complete. The centre wheelset is parked out of the way while two diesels reflect on a scene they remember well from the 1960s..

Close up of a section of Gibson Ring showing how it fits into the annular groove in the wheel centre. The tyre has a similar annular groove into which the ring is fitted. Once the ring is in place a lip on the back of the tyre is swaged over the top of the ring to hold it in place.

The old way of securing tyres----a redundant rivet hole..

Cracking along the line of one of the redundant rivet holes. Riley's assure us that a repair is straightforward.

Eccentric straps assembled in preparation for transport to Northern Ireland

We're Domed.....!

A mixture of good progress during the past week. Now that the loco is back on its wheels we can start refitting various parts and Roddie McCrae has been busy putting the loco brake hangers and railguards back in place. Likewise with the tender off of its wheels we were able to get the wheels and axles shot blasted to remove the years of accumulated paint and grime. This revealed some very interesting stamping on the tyres and wheel centres. As everyone knows, CR828 was delivered new from St Rollox works in August 1899 and as we might expect she has received various new parts during her long life. But it may be that she has been using a tender wheelset that's older than she is (see picture below). 

As you may recall we were unable to pressurise the boiler for hydraulic test purposes because of leakage at the regulator valve. Accessing the regulator meant that we had to remove the dome cover (28 large nuts to hammer off). Inspection of the valve showed that it was not seating tightly on its lower seat. The Caley were fond of using the Ramsbottom double beat regulator - as mentioned elsewhere it gives an easy and progressive opening with a relatively short travel. It relies on two valve ports, both of which operate simultaneously and both of which have to give a tight shut-off. What we found was that the upper valve was seating perfectly but the lower one had a significant sector where the valve plug was not contacting the valve seat. This was corrected by lapping with grinding paste (you have to lap both valves at the same time to ensure they remain fully aligned). Fortunately this is a relatively straightforward operation. You can sit on top of the boiler with your feet inside the dome mounting ring and use the weight of the valve to do most of the work for you. After getting a true seating for both valves the dome cover was refitted and the 28 nuts hammered tight in preparation for another hydraulic test attempt during week commencing 16th May.

Alan French, ably assisted by John Greig, completed the white metalling of the eccentric straps on May 14th. It was fascinating to watch Alan and John tackling this job - it requires real craftsmanship. We are now in a position to take the eccentrics and the straps across to the RPSI workshops at Whitehead for machining and fitting. When complete, I am sure that the loco will benefit greatly from having straps that truly fit the eccentrics for the first time in many years. It will be very interesting to set the valves again.

One slight setback occurred during the week when Ian Riley informed us that the tender tyre forgings have not yet left South Africa. This is a result of an export licence issue. Hopefully this will be resolved quickly and the tyres will arrive in the UK in around 3 - 4 weeks...

Concentrating hard, Alan French runs white metal into one of the eccentric straps..

A batch of eccentric strap halves (there are eight in total) lies cooling down after white metalling

John Greig and Alan French working together on the eccentric strap white-metalling production line..

Roddie McCrae fitting a brake hanger

And again, here's Roddie getting ready for another brake hanger

Removal of the dome exposes the Ramsbottom double beat regulator valve..

The regulator valve surrounded by the small steam take-off pipes for the injectors, the brake system and the blower. The large pipe is the main steam pipe that carries steam to the cylinders.

Despite appearances the boiler is in great condition. The operating rod for the regulator valve is connected to the regulator handle in the cab via an eccentric cam that raises and lowers the rod as the handle is moved towards open or closed.

The regulator valve stripped into its component parts. The operating rod is lying drunkenly against the steam pipes after its connecting pin has been removed. The valve plug has been removed and is sitting upside down on top of the boiler cladding. The upper and lower seats can be seen. 

After lapping in the valves with grinding paste this is what the valve seats look like. The continuous bright grey  lines indicate that the valve will sit tightly shut against the forthcoming hydraulic pressure (we hope...!)

Refilling the boiler before putting the dome back on....

The inside of the dome...a mixture of recent and old riveting..

The dome after having the copper sealing ring refitted (fully annealed)

The old girl with her dome refitted...

The tender wheelsets back from blasting and priming

No wonder we are renewing the tyres - this one has been in service since 1952...

Look at this.....one spoke has the word "Firth" stamped into it and the spoke above suggests that the date of manufacture was 10th June 1891......!!

The Old Six-Wheeler.....

Lots of activity in the last week. The loco has been put back on all six wheels and the tender has been lifted off of its wheels in preparation for retiring at Ian Riley's works in NW England. We also managed to lift the dome cover to find out why the regulator wasn't holding tight when we tried to pressurise the boiler with cold water. And Alan French has continued with preparing the eccentric straps for white-metalling. It was great getting the loco back on its wheels and nice to observe the good fit between LH Driving axlebox and the new Hornblock....

We have accepted an offer from the Railway Preservation Society of Ireland to get the eccentrics skimmed and the straps machined at their base at Whitehead near Belfast. The components will be transferred by van and will come back ready to fit. Some readers may recall that the RPSI did an excellent job of renewing crankpins on No.17's wheels a few years ago.

Throughout the week we had great support from Volunteers and Emplyees in the Engineering and C&W Departments. Grateful thanks to everyone who contributed.

The last of the many......driving home the last of the fitted bolts in the new LH Driving Hornblock. 

The new LH Driving Hornblock ready for action....

Eccentric straps ready for white-metalling. The countersunk brass screws will provide a strong bond for the white metal.

LH Big End Bearing fully blued / scraped and fitted is clamp around the crankpin using the temporary clamp made many years ago by John Crabtree.

Rolling out the crankaxle...it's heavy...!

CR828 admires her soon-to-be-refitted crankaxle and RH Driving Axlebox bearing

Draining the boiler before moving the loco to the Carriage Maintenance Shed for lifting and rewheeling

The loco is lifted once more by the C&W Dept jacking system; Nathan Lightowler grinds a chamfer on the new hornblock to help it slide into position as the loco is lowered..

Wheels in position and ready to lower away..

The new hornblock slides over the axlebox as the loco is lowered..

Shunting our six-wheeled loco back to the Engine Shed before turning the tender..

Tender on the turntable - we needed to turn it to make it easier to lift it and lower it onto the slave bogies.

Geoff and Keith roll out the trailing wheelset; the tender is lifted clear thanks to these marvellous electric jacks.

All 36 bolts hammered off of the dome and it's ready to be lifted to allow access to the regulator valve..

Inside the dome....the regulator valve is of the Ramsbottom double-beat type and gives a very easy and progressive control of steam flow to the cylinders. In this picture the valve is partially open. We need to remove the pin from the joint underneath the valve so that we can inspect the seating surfaces. The five open ended pipes are the steam supplies to the injectors, blower, brake and carriage warming valve.

The regulator valve in close up....