C2 Project News

August 2018

Here be Dragons!

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After the excitement of the Hunslet 125 event and the associated movements of our loco and tender frames, our working parties are returning to a more normal schedule. However, we took advantage of the bank holiday weekend for an extended work programme.
Work started on Thursday; Paul was rostered to drive an early-morning train but was free to get started in the C2 shed that afternoon. James had been firing for him, and offered to help on the C2 over the weekend too. Over the past two years we have done a lot of work on brake gear components, so Paul gathered everything together and compared them to the complete parts list. He then identified which parts are already complete and ready to fit, and compiled a list of jobs needed on the other components. He also had time to clean and paint a few brake slack adjuster parts. On Friday morning, Paul was joined by Mike, who tidied up some rough flame-cut edges on the brake gear equalising links.
Recently, Paul has spent a lot of time translating the Chinese maintenance and overhaul manuals for the C2. These include dimensional tolerances for the cylinder bores and alignment. Last month Erle did a preparatory rough measure of the cylinders, which indicated that they have been re-bored at some stage. On Friday, Paul carefully measured the spacing and squareness of the cylinder mounting pads on the loco frames, which are within tolerance.
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James was set the task of dismantling and cleaning up the rear cylinder covers, which we also wanted to measure.
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James cleans up the rear cylinder cover. On sunny days we prefer to do dusty jobs outside, where a selection of old wagons can be used as workbenches!
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Measuring the alignment of the mounting faces for the cylinders and the motion brackets.
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Measuring the cylinder bore diameters with an internal micrometer. Each bore was within a few thou along the length and round the diameter, but the two cylinders aren't the same size as each other at present.
Progress accelerated on Saturday morning with the arrival of Alan, Dave, Erle, and new volunteer Nick. After an induction, Nick and Dave worked together to refurbish two links from the tender brake gear, and make four new ones the same to replace others that were in very poor condition. On the tender handbrake column and trunnion, Erle drilled and tapped holes for grease nipples, gave the components a final clean and then painted them. He then cleaned up and bored out some more links from the tender brake gear.
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A collection of completed brake components on Saturday. The pile had got a lot bigger by the end of Monday. All of these have been cleaned up, painted, bored out and bushed; some have been made entirely new.
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The tender handbrake standard is now completely refurbished and painted, ready for reassembly.
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Erle sets up a brake gear equalising link on the Bridgeport mill, ready for boring out the holes to take new bushes. Where the existing holes were worn oval, a milling cutter was a far better tool for this than a drill.
James continued his work on the cylinder covers, helped at times by Paul and Alan who focused mostly on the cylinders themselves. They cleaned up the cylinder bores and took a series of accurate measurements. The bores are actually in very good condition with only a few thou of wear and a good surface finish. Paul also worked out how to measure the distance from the cylinder bore to the mounting face, confirming that these are parallel and within specification.

This is all good: it means we just need to skim the cylinder bores lightly to achieve a perfect bore, and we won’t need to fit liners.
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Alan measures the cylinder bores against a parallel. We also measured diameters at many locations along and around the bore, and checked the spacing of the bore from the cylinder mounting face. The bores are generally in very good condition.
A great surprise on Saturday was the appearance of a little creature in our shed. We've had a regular robin in the past, but this was a reptile. It was first spotted on top of the loco frames, and stayed in that general area all day. It’s a viviparous lizard, one of the commonest lizards in Europe and the only one found so far north. Given our Chinese theme, we named it 小龙 (Xiao Long; little dragon). It’s not an endangered species but apparently they’re rarely seen indoors like this. We saw it again on Sunday and on Monday, so perhaps it has taken up residence in a cozy shed that’s quiet for most of each month? We’ve only seen one at a time but it’s possible it’s not been the same animal each time.
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Xiao Long where we first spotted it; sitting on the box of the internal micrometer that we had been using to measure the cylinders.
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Xiao Long on the loco rear bufferbeam, which is covered with a dust sheet. The smokebox door is visible behind, stored against the shed wall. It's sticking its tongue out!
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Xiao Long seen on Monday, resting on a track sleeper. We assume it's the same animal we'd seen on the previous days but there could be more than one.
To set the cylinder and slidebar alignment perfectly, it is useful to set up a rod or wire on the cylinder centreline. On Sunday, Alan designed some cross-shaped jigs that would be a close fit in the cylinder entry bores and would provide an accurate datum for the centre of the bore. He spent Sunday and Monday fabricating and machining these. There’s a little more work still to do, but they will be very useful when we come to assemble the cylinders and motion.
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Alan cut and welded his X-shaped jigs from a strip of steel. This was an early stage in the fabrication process.
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The cylinder end bores are slightly different sizes so Alan is making a set of four of these X-shaped jigs.
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Alan takes the final cut on one of his X-shaped cylinder setup jigs, to make it a perfect fit in the cylinder bore.
Sunday also saw Erle, Dave and Nick continue to work on brake gear components, drilling and reaming out holes for bushes, also cleaning up and painting other components.
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Our new volunteer Nick helped Dave manufacture some replacement brake links for the tender. Here he removes scale from the plates ready for painting.
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Dave enlarges the holes in the eye of a brake linkage slack adjuster. When the existing holes are round, the radial arm drill does a quicker job than the milling machine, and the hole can be finished with a reamer.
Meanwhile James removed the studs from the cylinder covers (some of which needed encouragement with the oxy-acetylene torch). He then gave the cylinder covers a final clean, followed by painting with a high-temperature corrosion-resistant paint. Paul compared the measurements of the cylinders and frames to the overhaul specifications and worked out how to measure the critical dimension on the motion brackets too.
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James heats a recalcitrant stud with the oxy-acetylene. These studs attach the slidebar to the cylinder cover, and we will replace them with new. Heating the stud red-hot helps to free it from the tapped hole; it is allowed to cool before we extract it.
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Paul rigged up this arrangement with a height gauge to measure the motion brackets. The hole being measured is where the rear end of the slidebar is attached; it must be aligned with the cylinder centreline when they are attached to the frames.
The working party dropped back down to just 4 people on Monday: Erle, Dave, Alan and Paul. Nevertheless good progress was maintained. Paul assembled some of the completed brake slack adjuster components while Dave continued to ream out holes for bushes and Erle painted the completed components.
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An array of brake and cylinder components getting a first coat of paint. Four of the brake links are new, while the rest have been refurbished.
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These brake pull rods are all new, replacing worn-out old ones.
Erle then cleaned up the front cylinder covers; these are a simpler shape than the rear covers. Alan put the finishing touches to the first of his X-shaped jigs, and trial fitted it to a cylinder.
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This is one of the front cylinder covers which Erle cleaned up; we're making great progress with the cylinder components.
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An X-shaped jig trial fitted on one end of a cylinder. These will help us set up the cylinder and slidebar alignment.
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Erle fits plastic bushes into brake link components using the hydraulic press. This was the last task to be completed on much of the brake gear.
The final major task on Monday was to fit bushes to all the holes reamed in the brake gear components. Erle and Dave worked on this using the hydraulic press and a jig that Paul had made earlier.
All in all, this was a very enjoyable and rewarding working party. We completed a large number of brake gear components for both the loco and the tender, and we've made great progress with the cylinders and motion brackets. We're not far away from being able to trial-fit these to the frames for a careful measure up.
In September we hope to welcome some Russian guests to the C2 shed and show them our progress. They're from the Pereslavl Railway Museum and the Yekaterinburg Railway Museum. The C2 design originated in Russia and they have several Russian and European-built examples in their museums so we have plenty of common ground. And of course we'll keep our eye out for more sightings of the baby dragons!
September 2018