C2 Project News

October 2022

Working Party October 2022 - Boiler lift and busy times

The late October working party has been our busiest since 2019 as momentum builds after the lull during the global Covid-19 pandemic. We had 8 people in total working on the C2 over the course of an extended 4 day working party.

Friday 28th October

On Friday, Paul and Erle were the first arrivals with Andrew catching them up by lunchtime. While Erle continued to make the new governor weights for the turbogenerator governor in the machine shop, Paul and Andrew made preparations for everyone else turning up the following day which included finding tools, materials and equipment.
On arrival Friday, Erle set too with making a key to fit into the Turbine Generator Shaft. This engages with the broached slot formed in the Turbine Body. The key was cut to length and both ends radiused to match with the slot in the shaft. A small notch was formed at one end for the Governor Body to fit over whilst still engaging with the Taper Sleeve which locks everything together.
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New key for the turbine shaft. - Erle Ford
With the key fitted, the Turbine was lightly clamped in place and rotated together for the first time. This gave the opportunity for some checks with a DTI to measure the Turbine run out and end float for the first time. These all look promising.
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New turbine trial fitted to the shaft:- Erle Ford
The next job was the Retaining Band profile. The 110 profiled holes were all checked with a loose Turbine Blade to ensure the profile would fit over them successfully. A further check was a diameteral measurement with a large vernier calliper across the Turbine Blade shoulders. This is a critical measurement. If to big or too small the pierced holes in the retaining band will slowly get out of step with the Turbine Blades when fitted. All appeared OK.
With this result, the next job was to tackle rolling the Retaining Band to shape. The workshop has a small sheet metal roller and this was used to form the profile to diameter. The length of the profile had been made longer than needed as the first section remains straight until it contacts the roller. This will be cut off to length later on.
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Rolling the turbine blade retaining band. - Erle Ford

Saturday 29th October

On Saturday, Paul, Erle and Andrew were joined again by Bobby and Dave 2. In addition, after a gap of a few years since he last helped with the C2, Alistair turned up again to help. Alistair was present with us in China back in 2005 when we first discovered Dahuichang #4). We hope that we will see him more often in the future. Another attendee, new to the C2 project was Dave (another one 3?) who has previously volunteered at Boston Lodge a few years ago and brings with him his engineering knowledge and miniature railway experience.
The main jobs for the day were to complete the final preparations for lifting and mounting the boiler on the frames. Although, we will be making a new boiler, mounting the existing boiler will allow us to continue re-constructing the locomotive while we wait for the new boiler. A boiler swap will then be required at a later date. Dave fettled the rear diaphragm plate and its associated packer pieces to make them fit. The rear diaphragm plate is essentially the interface between the rear of the boiler and the loco frames. Not only does it support the weight of the fire box and rear of the boiler but it is flexible and allows the boiler to expand as it heats up. The fettling required some milling, drilling and removal of paint from bolt holes in the frames. These components were all then painted with primer before the end of the day. Dave 3, as new to the project volunteered to take on the messiest job, that of cleaning out the firebox of loose rust/scale build up over the years. We had decided that prior to mounting the boiler, we wanted to clean it up and paint it, to prevent it from shedding rust over where we will be working on the lower parts of the locomotive. This also applied to inside the fire box. Wearing a full face mask with particulate filters and hearing protection, Dave 3 climbed into the firebox armed with a wire wheel mounted on an angle grinder. After an hour or so (and a couple of breaks) Dave emerged covered in rust that he cleaned off the inside of the fire box. In reality he wasn’t as bad as you might imagine as Paul and Andrew had set up an air extraction blower the day before which proved very successful. Thank you for doing this particularly messy and unpleasant job Dave! Andrew and Dave were able to apply the paint later in the afternoon, or at least most of it before the paint fumes became too strong in the confined space, even with the forced ventilation that we had set up.
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Cleaning and painting inside the firebox using forced air extraction. A full face mask with particulate filters was also used. Thanks Dave for your efforts. A thoroughly unpleasant job for you. - Andrew Nelms
Whilst all of this was going on, Alastair and Bobby worked on making brackets for the tender break gear. These brackets are designed to catch the break rigging in the event of a failure and stop them from digging into the ballast. This is an important safety feature. It involved cutting, drilling and bending some flat bar.
Erle was busy at work too, continuing the machining of the Governor Balance Weights on the Bridgeport milling machine. The day was spent setting up the work in V blocks and milling out the 45deg inside face and then the face which the claws feet will be formed from, which was duly completed.

Sunday 30th October

The main objective for Sunday morning was to get the boiler back onto the locomotive frames. This started with a tidy-up of the equipment which had been used previously; Dave 2 taking the air extraction equipment back to the Erecting Shop. Paul rounded up the necessary lifting equipment.
Andrew and Dave 1 fired up the Castle Aarrgghh diesel shunter and, between heavy rain showers, used it to shunt things into position. First the wagon carrying the boiler had to be moved out of the C2 Shed into the adjacent Carriage Shed. Then the locomotive frames could be moved from the back of the C2 Shed into another road in the Carriage Shed. Next, the wagon and boiler was brought back into the C2 Shed and positioned under the A-frame crane.
Alastair and Daves 1, 2 and 3 wrapped the straps and chains around the boiler, using Paul's photographs from previous boiler lifts to make sure that leg lengths were correct to ensure a straight lift. With the crane taking up the slack, a problem then showed up. The boiler would have to be lifted high enough to clear the cylinders, motion brackets and cab brackets on the locomotive chassis. A quick measurement of these parts showed that we needed 41 inches clearance above rail level. It was readily apparent that we did not have enough travel on the crane, which meant we could not lift the boiler high enough. A quick re-arrangement of the shackles being used gained us about 5 inches of travel, but we were still about 9 inches short.
The A-frame crane has castors (small wheels) under it, but also has screw jacks at each corner to stabilise it during use. There was about 12 inches clear between the top of the A-frame and the C2 Shed roof, so we used the jacks to lift the crane castors off the ground. Packing of the castors and A-frame base girders with old railway sleepers lifted the whole crane upwards, thereby gaining us the required extra height. Great care was taken to ensure that the crane was stable and well supported, just as it would be if on the ground.
With adequate travel on the crane, the boiler could now be lifted off the wagon. The wagon was pushed out of the C2 Shed and onto an adjacent siding behind the Carriage Works. The locomotive chassis was then shunted back into the C2 Shed under the boiler. Fortunately the measurements proved correct, and the high parts of the chassis all cleared the bottom of the boiler by an inch or two.
Preparing to lift the boiler - Andrew Nelms
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It was then time to lower the boiler onto the chassis. The notches which Paul had ground into the smokebox saddle base had to line up with the ribs on the back of the cylinders, so this was the first thing to align. The initial lowering of the boiler appeared to result in it jamming between the cylinders, causing some consternation. But lifting the boiler marginally, and making sure it was centred between the cylinders, resulted in the smokebox saddle sitting comfortably down onto the support pad at the front of the chassis.
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Lowering the boiler onto the frames - Paul Molyneux-Berry
The rear of the boiler should be supported on a diaphragm plate (with fitted bolts carrying the load), but the Chinese had welded small pads onto the locomotive frames under the front of the foundation ring to avoid the complication of using fitted bolts. With the foundation ring sat down on the pads, the boiler was definitely tilted backwards a little. Andrew and Bobby assisted with the fitting of the rear diaphragm plate, which required the rear of the boiler to be lifted clear of the foundation ring pads. This seemed to level the boiler again. Packing was placed between the frame pads and the foundation ring to help carry the weight of the boiler, since we are not fitting a centre diaphragm plate at this stage.
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Boiler newly fitted back onto the frames. Left to right: Dave 2, Dave 3, Bobby (inside firebox) and Alasdair. - Andrew Nelms
While we had been cleaning the boiler, the tender chassis had been stored under cover in other parts of the Boston Lodge site. With space at Boston Lodge always at a premium, we did not want to outstay our welcome, so next task was to retrieve the tender chassis and get it back into the C2 Shed. Andrew and Dave 2 located the tender chassis buried inside Sied Gwlyb, so shunted all the stock around to extract it. Dave 3 was very keen to see the tender coupled to the correct end of the locomotive, and persuaded us to do so. This was to prove useful later on.
With all the major parts of the locomotive assembled in the correct order an opportunity was taken to photograph the locomotive outside, although the brief moment of sunshine had passed by the time we had got into position. This is the first time that the locomotive has has a boiler on it while its wheels are on 1′11½″ gauge track; quite a momentous moment!
Loco and tender re-united with the boiler - Andrew Nelms
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While all this was going on. Dave 1 and Paul discussed the gauging of the locomotive. Paul had carried out calculations, comparing the locomotive (and particularly the cab) to the Ffestiniog Railway loading gauge and to known infrastructure tight spots. Paul had also measured the cab of Lyd, which is known to occasionally scrape the inside of Garnedd tunnel! Putting together all of this information allowed him to conclude that the width we have chosen for the cab floor will not cause any gauging problems. Dave 1 reviewed the calculations and agreed. This now allows physical progress to be made on the cab.
Before Erle had to leave us after lunch on Sunday, further work was carried on with the Governor Balance Weights. To form the claw feet a 28 mm radius is needed between them. The radius is machined at a 15 deg angle, which was going to be tricky to produce. At a previous working party a rotating machine vice was identified in the C2 shed which would help set the angle up. A look at the vice showed it needed some restoration work on it. Two clamping bolts holding the rotating vice to its main body were seized. After some work with lubricating oil it became apparent the socket screws were not coming free easily. The vice was then taken over to the Erecting Shop where some brackets were being heat formed by the team. With the use of the welding torch and a bit of heat and the use of Stilsons the socket screws came free. The rest of the afternoon was spent finding new replacements and replacing the missing guide screws and cleaning some of the rust from it. A bit more TLC will see it usable to continue the milling of the Governor Weights at the next WP.
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Machining the balance weights. - Erle Ford
Due to a very busy morning, a late lunch was had, after which people started to drift away and head for home. Andrew, Bobby and Dave 1 remained, and spent what was left of the afternoon tidying up the C2 Shed.

Monday 31st October

Andrew and Dave 1 spent an extra day at Boston Lodge after the main working party.
Andrew had noticed that the boiler appears to be sitting rather higher relative to the cab brackets than his drawings had indicated. This needed investigation. He and Dave 1 spent a considerable amount of time measuring the height of the boiler relative to the locomotive frames, and relative to the cab brackets. After a morning's work, they concluded that the rear of the boiler is probably sitting a few millimetres high, the cab brackets are a millimetre or two low, and the discrepancy is amplified by an optical illusion resulting from the angle at which the two are normally viewed at! Now that we understand what is going on we can make any corrections necessary and proceed with the cab design with confidence.
Having the engine and tender chassis coupled together correctly makes it possible to measure the clearances between the two. Andrew used the Castle Aarrgghh to pull the locomotive very slowly out of the C2 Shed while Dave 1 measured the clearances. When we reconstructed the tender chassis frames some years ago, we discovered that one of the bulkheads was about 15mm further back than shown on the original drawings. This bulkhead had been used to position the drawbar pivot at the tender end, and so has resulted in the engine and tender being 15mm closer together than we originally intended. The cab design overhangs the rear bufferbeam by 110mm, so eating into the space between engine and tender.
The track in the C2 Shed is not perfectly aligned, there being a kink just inside the door. With the engine-tender drawbar above the kink, the gap between engine and tender chassis is 105mm which indicates that the cab, as designed, would foul the tender frames. Further out of the shed, where the track is better aligned, the clearance as 125mm. This all tells us that we need to give the engine-tender interface some more though. Do we shorten the cab (undesirable), make a longer drawbar (and scrap the existing one), or is the track kink excessive? At least we've found out now rather than when the locomotive is complete.
The long angle iron sections for making the cab floor had been laid outside the C2 Shed all weekend, and we were getting fed up with stepping over them! So Andrew marked up the lengths which would be needed, and Dave 1 used a cutting disc to cut the angle iron into the appropriate lengths. The parts are now much easier to manhandle. To keep them out of the way, Dave placed them in their approximate positions on the rear of the locomotive chassis. Although currently all the sections are a little over length, it starts to give us a good idea of how the cab floor will be constructed, and how big the cab will be.
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The frame for the new cab floor cut and put in place to demonstrate the basic structure. - Andrew Nelms
While Dave 1 was cutting up the angle iron, Andrew was painting the rear diaphragm plate and cab bracket bolts to prevent them corroding.
Since arriving at home, Erle has commenced fitting of the Retaining Band. One difficulty he had was that he did not realise that the piercings in the Retaining Band are set to its fitted position which is fine. However the tops of the blades are splayed further apart when fitting. So Erle borrowed his son's Dremel and with a small diamond grinder he's taking a small bit off one side of the peg and with a bit of tapping with a drift he's got about a third way around and still going....
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Fitting the retaining band to the turbine at home: Erle Ford
November 2022 
September 2022