November 2019 – News Letter

Preamble

I’d planned to have something out in October, a respectable three months on from the previous issue, but life has an irritating habit of getting in the way of things. As Edmund Blackadder so eloquently put it – “The path of my life is strewn with cowpats from the Devil’s own Satanic herd”. Be assured, however, that I’ve swept up and what follows is wholly fragrant ….

Around and About the Club

Big things have been happening out on the grass of late as work has progressed steadily with building the new Carriage Shed for the raised-track riding trucks. Many cubic metres of soil have been excavated to prepare the ground for the floor-slab (6m long by 2m wide by 10cm deep) which sits several centimetres below the surrounding ground level. Four courses of blockwork are raised on this to roof-eaves level. A door-frame and sill have been fabricated in steel which occupy the full width of the track-ward end. Provision is made in the floor to bring in mains electricity.

Whilst the ground works for the carriage shed were underway, the area in front of the locomotive shed was also prepared to accommodate the new dual-gauge traverser and the slab for this was poured at the same time.

Work also continues with improvements to the track signalling and point control systems. Receiving attention now are the points between the station loop and main line so that these cannot be operated whilst a train is in transit. Additional train-detectors have been installed in the track and associated cables laid-in back to the Signal Box where a new cabinet houses the extra circuitry required.

Creosote Day, Saturday 7th September, witnessed a good turnout of willing helpers to get this annual maintenance job done. Both ground-level and raised tracks were thoroughly treated using a combination of spray-guns and brushes.

If you’ve visited the TSMEE website recently, you’ll have noticed a quite radical change in appearance and content. John Rowley has taken over the job of webmaster and is keen to stress that it is, presently, very much “work in progress”. User feedback and constructive comments are welcomed.

Events …

Open Weekend 27/28th July

This annual two-day event was not blessed with particularly good weather. It rained on-and-off on the Saturday and Sunday was dry but overcast. Nevertheless, there was a respectable turnout of both TSMEE members and visitors, the latter hailing from as far afield as Scotland, Cumbria, York and Leeds.

Visiting locomotives were :– in 3-1/2” gauge  BR “Britannia” 4-6-2, Great Central O4 2-8-0, Freelance 4-8-2 – in 5” gauge  “Chub” 0-4-0 Tank, BR Standard 4 2-6-4 Tank, NER Q6 0-8-0, NER B2 4-6-0 – and in 7-1/4” gauge  GWR 14XX 0-4-2 Tank .

Saturday lunch was Fish ‘n Chips and on Sunday our Catering Stalwarts laid on their usual splendid buffet.

Trip down the Tyne 31st August 2019

Six members joined our party on the “Fortuna” for a cruise down to Tynemouth from the Quayside in Newcastle. The weather was reasonable, even allowing for the blustery wind, and we all enjoyed the trip.

There is a full and very informative commentary on the way to Tynemouth. I have made the trip a couple of times over the years and I am amazed by the way that Tyneside industrial heritage has disappeared in a comparatively short time. It used to be the remains of ship yards, dry docks and associated industries all the way to Tynemouth. Now much of the bank-side is wooded and under modern housing. It all looks very different.

The remaining working areas are impressive and Tyne Dock is massive. The Fish Quay and Tynemouth with the Harbour Lights, like much else of the riverside, are becoming tourist attractions. That’s progress, so we all went to the bar and drank to the past.   Malcolm Phillips

Trip to see the G5 at Shildon and the P2 under construction at Darlington, 7th October 2019.

Another enjoyable day out, perhaps more related to model engineering. Volunteers at both sites were very helpful and thanks are due to Phil Work who kindly arranged tea and biscuits at Shildon.

The G5 is not quite an engine yet, but most of the parts are ready to go together. The frames, boiler, cab and plate-work just need finishing touches. The bogie for the 0-4-4 and one set of driving wheels have been finished but the crank axle has yet to arrive, as manufacture of parts and machining is all done outside. The group has been working to original plans and has had to make many patterns, some of which are placed beside the finished castings.

From Shildon we proceeded to Darlington. The P2, to be named “Prince of Wales”, is a truly impressive machine. Like the G5 it has yet to go onto its wheels, all of which have had their tyres polished to a mirror finish.  Cab and smokebox are on the frames and the boiler cladding is set up on frames beside the locomotive as the boiler is yet to come from Meiningen.

We were told about some of the technical problems – the wheel flanges have been computer designed to ease passage round curves on Heritage Railways and steam distribution will be by poppet valves.

The original Gresley design was not too successful so the designers have used the designs evolved in America after the war which were better. Boiler design has been modified by experience with Tornado and their boilers are interchangeable.

I do not know what will become of the polished wheels – one of the volunteers told me that the painters were upset because on its first trip to York of thirty miles, their beautiful paint finish was spoiled by excess grease and oil coming out of the axle boxes!

The NELPG shops were closed so we completed the trip with a visit to the Head of Steam Museum across the way from the Hopetown works. This is a nice museum with exhibits of Stockton and Darlington and NER origin. Hackworth’s “Derwent” and “Locomotion” are well displayed and there are some interesting small exhibits.   Malcolm Phillips

For your diary …

Public Running Day – Santa Special – Sunday 1st December

Christmas Tea – Sunday 22nd December

Something a bit different now – Gordon Bullard has very kindly submitted the following rather interesting article…

An Automatic Cylinder Drain-cock

Back in the 1980’s over a pie and a pint in a local hostelry, a friend and I were discussing the pros and cons of cylinder drain cocks and associated linkage to the cab of a miniature steam locomotive. 

The locomotive he was building had two sets of Stephenson’s valve gear and an axle pump between the frames, together with lubricator linkage which left little room for direct drain- cock rodding.   We discussed the possibility of automatic drain cocks and I suggested that a small inverted safety valve type of arrangement might be possible.

A set of small valves was made and fitted, each consisting of a stainless ball which was held on its seat by a small bronze spring.  The valves performed well but they looked like upside-down safety valves, which is, of course, exactly what they were.

Clearly, a horizontal arrangement was required which would be more prototypical of full sized practice. So, another set of valves was made in a tee configuration with basically the same internal arrangement but in a horizontal orientation.

These valves worked reasonably well. They certainly cleared the cylinder condensate very efficiently but for some reason when the locomotive was running slight puffs of steam were occasionally noticeable. 

Closer observation showed that one of the valves seemed to be working well with no visible leakage whilst the loco was running.  With the expectation that the poor sealing of the three sub standard valves was probable due to poor workmanship on my part,  all of the valves were disassembled for examination.

I was amazed to find that I had forgotten to put a spring in the valve that worked perfectly.  The valves were quickly reassembled without springs and found to all work perfectly.  Since then I have fitted this type of valve onto three of my locomotives with no failures.  The last loco was to LBSC’s “Maisie” design and has run on the club track on numerous occasions.  The attached drawing shows the design of the valve which is made of bar material with a silver-soldered joint.

 It took a while to work out how the valve worked without a spring.  When the locomotive is stationary any condensation in the cylinder drains down into the valve where the ball is resting on the bottom of the chamber so any water can drain away via the front hole. 

When the regulator is opened a combination of condensate and steam enters the valve where the ball is unable to seat properly due to the turbulence in the chamber.  A combination of water and steam exits the valve due to this turbulence until all of the water is displaced, which leaves the chamber full of steam which in turn forces the ball onto its seat.  It’s as simple as that.

You may well ask what the reduced diameter on the rear of the valve is for.  It is purely there to improve the fitting visually, disguising the fact that it is just a piece of simple bar material.  For members who follow full size practice and require drain piping to the locomotive’s buffer beam,  the front of the valve seat could have a small ME thread machined onto it to take a nut, nipple and associated pipe.

In conclusion, this simple valve is easy to produce, is fully automatic in operation and requires no linkage to the cab.  It would be easy to say that I had a light bulb type of moment concerning this valve’s conception but in reality it came about more by accident than design.

Drain-cocks fitted to 3-1/2″ “Maisie”

Postamble

As I remarked in the previous issue, a Newsletter requires News, and this one would have been a rather thin affair but for the contributions of Malcolm Phillips and Gordon Bullard. My thanks to them both.

Membership Subscriptions will be due for renewal at the end of the year. The cost remains at £35 Single and £45 Family. Our Treasurer Ian Spencer will take payment in cash or cheques (payable to “TSMEE Ltd”).

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A last machining operation on the axleboxes was to profile the bottoms
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Set of six axleboxes on a copy of the working drawing
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A driving box in place in the guide
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A temporary axle was made to check the alignment of the axlebox pairs when fitted in the guides. A bit of careful filing and scraping corrected the fit
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Both sets of frames with the axleboxes in place
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A coupled axle in the lathe between centres for rough machining
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A toolmakers clamp on the lathe bed provides a back stop whilst reducing the centre of the axle, The head end of the machine has a saddle stop.
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A journal being finish machined
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A pair of axleboxes on an axle
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Coupled axles in place on the frames
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A crank web bored for the axle and crank pin and the keyways broached
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The axle drawing with revisions over several years as the project developed on paper.
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Roughed out driving axle ends ready for machining of the keyways
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Keyway machining
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Axle stub with finished keyway
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Axle stubs and crank web blanks
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Machining a pair of crank webs (1)
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Machining a pair of crank webs (2)
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Machining a pair of crank webs (3)
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Machining a pair of crank webs (4)
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Machining a pair of crank webs (5)
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Finished crank webs ready to receive axles and crank pins
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Crank web with axle end pressed in after facing off
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Crank axle being Drilled for dowels
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Keyways to crank pins being machined
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Crank pins with keyways ready for finishing and final assembly by pressing into webs
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Crank pin after pressing in to web
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Assembled crank axle
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Crank axle set up on rotary table for drilling dowel
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Assembled and dowelled crank axles ready for finish machining
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A crank axle set up between centres for final machining. Note the wheel seats are left oversize until the wheels are bored. As these are a taper fit, once the machine is set to cut the tapers the wheel seats and the wheel bores are finally machined to the same taper setting.
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A driving wheel casting set up for facing the back
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Facing in progress
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A wheel set up for boring. The centre is located by measurement from the inside of the wheel rim. As this may not be truly circular some judgement is required on determination of the best location
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Starting the bore
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Drilling the bore
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Boring in progress
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Once all the wheels are carefully bored to the same diameter a mandrel is made to fit in in the lathe spindle taper and used to set up the wheels for all further machining operations in the lathe and on the rotary table on the milling machine. A wheel is seen set up for facing
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Facing the tyre
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Facing and profiling the centre
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Machining the inside edge of the tyre. Note at this stage there was no intent to fit steel tyres. That came later.
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Machining the groove at the balance weight
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Chamfering the edge of the balance weight
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Rough machining of the tyre profile. Final profiling should be done after the wheels are pressed on to the axles to correct any run out that may develop
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Back in the milling machine for rounding the back of the spokes. The wheels were reversed and the front of the spokes were also machined with a radius cutter.
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The spokes as cast were not perfectly regular in spacing and thickness and had some casting defects. Whilst time consuming the end result is a great improvement on the original cast.
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The final operation was to finish the spokes by hand with a round file.
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A typical casting fault in a spoke
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An epoxy metal filler was used to finish the wheels where machining had not completely removed the defects. After curing the filler is easily smoothed by hand with a fil
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The wheels were then returned to the lathe, trued using a dial test indicator on the tyre and bored to a taper of 2 thousandths of an inch in the wheel thickness.
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Once the wheels were bored the axles were returned to the machine and the wheel seats were machine to the same taper such that the axle would enter the wheel bore by a third of the length of the seat. When the wheel was pressed home this gave an interference fit of 1.5 thousands of an inch, a little over the recommended thou per inch.
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An offset mandrel was made and fitted to the face plate for boring and reaming the crank pin holes
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The holes were started with a centre before drilling
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And finished with a reamer
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A jig was made up to hold the broaching guides for the crank webs and this was modified and reused for the wheels to ensure the axle keyway was exactly in line with the crank pin centre
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A setting block was used to align the broach guides
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The wheel press was used to drive the broach for the keyway
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The coupled wheel crank pins ready to be for pressing in to the wheels.
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The driving crank pins were made as a pair and one is seen having the keyways cut using a between centres set up in the milling machine.
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The rotary table was used to set the angle for machining the square for the return crank, accuracy being essential for correct operation of the valve gear.
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The crank pins machined and ready to be separated
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The same between centres set up in the milling machine was used to cut the keyways in the axles. These needed to be accurately machined at 120 degrees so the cranks would be "quartered" as the wheels were pressed on.
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Cutting an axle keyway
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The other end after rotating the axle 120 degrees
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The wheels are fitted to the axles with the keys on place and put in the wheel press.
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They should press on equally confirming the press fits are the same.
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The crank axles need setting up carefully in order to get the correct relationship between the centre and outside cranks.
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The wheel sets all complete save final profiling of the tyres and fitted in the frames. Making the wheel sets took until November 2010, about 9 months from starting.

Contact info …

Newsletter Editor – Mike Maguire ~ mike.maguire@btinternet.com

Club Secretary – Linda Nicholls – lindanic@sky.com ~ 01 670 816072

Website – John Rowley – webmaster@tsmee.co.uk ~ 07970 164 967

For your information – a PDF copy of this News Letter can be downloaded here ….