Steam at the end of the Tunnel...

It's been a long time since Joyce's original superheater (SH) blew a hole in June 2022. Getting a new one up and running has not been easy but I'm now only a few odd jobs away from being ready to do a test firing.

Despite all the difficulties, I did eventually receive the SH but it arrived as a poorly assembled kit of parts.

I'm very grateful to my friends at the North Yorkshire Moors Railway (NYMR) for helping me with transport logistics.

On initial examination, it was obvious that the coils were not secured properly; they had shifted and were no longer properly supported.

These photos illustrate the point.

Centre of photo shows coil clamps (Upper is displaced)

Coil spacers poking out on one side correctly...

 

...But not on the other side

RH bottom clamp out of line and not supporting inner coil

I did of course make this known to RBS but was assured that it was fine when it left them and denied all responsibility.

Let's consider this:

1. It's a superheater required to operate in a very harsh environment whilst being continually shaken, rattled and rolled by the surrounding steam loco. If it cannot survive a ride in a van, it is not fit to be in a steam locomotive.

2. On collection from RBS, I was told by the NYMR driver that it had been unceremoniously dumped outside RBS leaving the driver no option but to borrow a fork lift truck from a neighbouring company to put it into his van. 

These photos were taken at NYMR on my collection visit.

My first view of the completed unit

Same location - the clamps were already displaced
Note the SH spreader plates tied on, not fitted

Welded locking bar

So why had this happened?

I removed the two welded locking bars and loosened the two supporting struts and did my best to pull things back into shape. However, I had limited facilities and could not make any impression on it.

I did however try taking off the top plate and substituting ½” spacers under the large nuts. The idea being that with the top plate out of the way, I would have better access to pull things into shape. But to no avail.

It was at this point that I realised why the coils had shifted. When I tried to tighten one of the clamping brackets with the ½” spacer present, I found that I could not tighten the clamp down on the coils because the nut had reached the end of the threads on the supporting strut.

As such, with the top plate in place, it would not be possible to clamp the coils securely.

In the next photo, the fixing rods are shown protruding through the brackets but there is insufficient thread to tighten the brackets and secure the coils.

Limited thread on the struts

My conclusion at this point was that, although the coils were actually pretty good, the unit as a whole was not fit for purpose - certainly not the ready-to-drop-straight-in item I had ordered.

So what next? 

When I had originally begun looking for someone to make the new SH, I started with JR Goold Steam Ltd whom I had worked with during Joyce's restoration. They were unable to do the tube bending, however, given completed coils, the job was now well within JR Goold's capabilities. They had also done the same work first time round during Joyce's restoration.

(Check out https://www.gooldsteam.com/sentinel_superheaters).

I was certainly not prepared to continue with RBS for obvious reasons. (https://sentinel7109.blogspot.com/2024/04/renewing-joyces-superheater-1.html).

Initially I discussed the problems with JRGS referring to a Sentinel boiler drawing similar to Joyce's and photos of the problem shown above.

These were my requirements:

1. Flatten the top plate so that the funnel bases will seal properly. There is a dip in the middle of the cross-piece at present.

2. Make the necessary spacers to hang the SH coils properly from the top plate.

3. Reassemble the tubing and top plate and tighten the coils in place.

I also provided some dimensions as to where the tube flanges would need to be should any adjustment be necessary.

A few weeks later all was complete and I asked Peter Hawkins, Joyce's boiler inspector since 2009, to examine it before accepting from JRGS. All was well and a preliminary certificate was issued covering the work and giving me the go-ahead to reassemble all into Joyce ready for a test steaming to check for anything untoward. A formal inspection run would follow as in previous annual inspections. (The test run is to make sure that all is well - Boiler inspectors still have to be paid even if they don't issue a certificate).

The final unit from JRGS

Clamps holding the coils correctly

New spacers supporting coils on one side...

...and on the other

Clamps in line and supporting the coils

The unit followed by the funnels was craned-in with help from local company R J King Ltd. Their driver, Paul, had craned in the entire boiler back in October 2011 and so it was almost a repeat performance for him.

Sky Hook?

And seated!

Watch this space.

Chuff Proofing (3)

In Chuff Proofing (2), I showed the 'completed' superheater steady plates for both inlets and outlets. I later realised that one of the screw fixings was loose and would need to be enlarged from 3/8" BSW to M12 and the hole re-tapped for a secure fit.

M12 screw highlighted on plates at the rear
(i.e. nearer the regulator)

Having enlarged the one I knew about, when checking, I found two more loose ones on the plates towards the cab front.

M12 screws highlighted on the plates at the front
(i.e. superheater inlet)

Hopefully these will all be secure in the long term and rattle proof. (I hate rattling noises).

Vacuum Braking (13) Implementation (7)

Sunday May 31st 2015 has been mainly about the vacuum braking pipework but not entirely.

In my last article, I'd begun to assemble the vacuum ejector pipework. Now I've pretty well completed it as shown below.

Steam supply linked to the Ejector

The main work was either side of the blue pressure reducing valve (PRV).

PRV, condensate drain valve and unions at either end

Both upright ends had to be parallel in order to mate with the union counter parts. (If I've not said before, unions allow the pipework to be taken apart and also enable rotation).

In the above photo, there are unions at each end of the pipe but, in the first photo, the upright larger diameter pipe also has unions allowing it to rotate. In this way, the distance between the PRV and ejector has been made non-critical and hence much easier to assemble.

The next task was to add some support for the vacuum hoses. Previously the 'Swan necks' on the buffer beams had left only a short length of pipe to attach the hose. I'd felt that some extra length was needed in case the hose could lever itself off.

Lengthened 'Swan neck'

The extension was made from a straight pipe coupling and spare male threaded pipe. The threads were sealed with Heldite.

Comparison with usual hose attachment

The extension is still a little short compared to a normal hose fixing. However, if there is a tendency for hoses to come adrift, the extension can be extended further to fix the problem!

Some time ago, I decided that I wanted to take the steam supply for the whistle and pressure gauge from the safety valve assembly instead of the two outlets at the ends of the four-way manifold which feeds the superheater. It saves one expensive isolating valve and make the valve actually reachable by hand!

I thus had to block the manifold outlets. I used a heavy duty steel cap for one end and a coupling and plug for the other (I had the cap already and I couldn't get another off the shelf).

Since these items were round, I was advised that a Stillson wrench was the best way to tighten them despite the likelihood of some surface damage in the process.

Screwing it up!

To ensure a good seal, I made a pair of thick annealed copper washers and applied a liberal amount of Steamseal to make sure.

The cap fits

The Plug fits!

Now to make a hole in the roof for the ejector exhaust.

Unexpected Surprise

A very cold Monday 2nd Feb. started with an attempt to repaint the cab roof. The first problem was that the paint was so cold it had the consistency of Tar! Leaving the paint tin in hot water for a while turned its contents back to liquid.

Problem solved so I thought but only to be thwarted by 7109 being chilled to the core overnight in Midsomer Norton's goods shed. As soon as the paint touched the cold metal, it went back to tar and couldn't be spread. I gave up at this point.

Nigel (co-owner) appeared with two sheets of the cold steel to make a pair of superheater steady plates something like in the drawing below (apologies for the low resolution). These are screwed to the boiler top plate around the superheater tubes to eliminate leakage of air into the boiler's superheater space every time there is a 'chuff'. Each 'chuff' is supposed to draw air up through the fire not in via the leaks! I'll come back to this another time.

Superheater steady plate drawing

We had a visit from Mr S., an S&DRHT member whom I'd not met before. I showed him over 7109 in my usual manner. He remarked that he followed the blog and enjoyed seeing the progress. To my great surprise, he delved into his pocket and produced a modern version of the item below to make us a donation. This immediately paid for the just-purchased cold steel mentioned above!

Oldie but Goodie

Many thanks Mr S. May more visitors such as yourself please come and see us at work and be shown 7109's secrets! (If you can't visit in person, there's always this as an alternative!).

Work continued with attempting to persuade the boiler cover to fit. I have to admit that part way through the afternoon, I had to give up due to the cold. When the entire loco is freezing cold, every touch of the cold metal, whether it's feet or hands, loses a little more body heat. I'd run out!

Next Saturday 7th Feb. 2015 is the Sentinel Drivers Club AGM for the group of stalwarts who support all things Sentinel, including 7109.

Boiler Fittings (6)

At the end of my last article on the boiler fittings, I was left having to think a while as to how to make the superheater actually fit its fittings.

I realised that the boiler top-plate and four superheater rings were all tightly fixed together by their mountings. As a result, I was having to cajole each ring against the wishes of the rest of the rings.

By loosening the fixings, each ring could be adjusted independently of the others and of the boiler top-plate leaving much more slack to play with.

So after some careful height adjustment with the sky-hook, here's the result.

Regulator and superheater connection (1)

Regulator and superheater connection (2)

Not obvious in these photos is the use of 2mm thick annealed copper washers to seal the mating faces of the superheater joints.

Steam feed manifold (1)

Steam feed manifold (2)

Steam feed manifold (3)

My apologies for the poorer quality of these photos, I forgot my usual Canon Powershot S95 and had to resort to a mobile phone!

If you are still wondering about the skyhook, click here!

Boiler (Not) Fittings (5)

Having fitted the steam feed manifold and regulator assembly to the boiler, the next job is to join them together using the 4-ring superheater.

I recall being hugely relieved when I was told in June 2011 that our superheater was new old stock and had never been used before. Brilliant, I thought; however, there is a down side to this in that it has also never been joined to a set of steam fittings before... Could this mean that it might not fit first time 'out of the box'?

Have a look at these:

Superheater not quite above the regulator assembly

Superheater not quite above the steam feed manifold

In fact, the superheater really does not align very well at all! I decided on Monday 4th March that it was time to put this aside and think about it for a while!

Not only do the fittings not line up but when they eventually are 'persuaded' into place, the boiler top plate will then not align with the boiler top itself!

In 1973, during my student apprenticeship in Newcastle, I spent 6 weeks in a fitting shop at C A Parsons & Co Ltd, the sadly long-gone Turbine-Generator manufacturer. I never thought I'd ever find that experience useful again - little did I know what I'd need in later life!

Boiler Fittings (3)

Having struggled with radially diverging screws for the steam feed manifold at the front of the boiler, many of the others have proved much easier.

Double flanged adapter for the safety valves
(This was the first gasket I made - I did improve later!)

Single Clack (non-return) valve for the cab's boiler feed pump

Double Clack (non-return) valve for the two engine-mounted boiler feed pumps

And, after about four attempts, the steam feed manifold!

The steam feed manifold (1)

This has been an educational exercise in screw-bending and grinding, drilling and filing fixing holes to fit and grinding the steam aperture in the manifold casting; not forgetting the removal of some solidified graphite grease getting in the way!

The steam feed manifold (2)

The next item to be fitted is the regulator valve assembly on the rear of the boiler. Hopefully it will then be possible to lower the superheater back into place on the regulator valve assembly and steam feed manifold. Looking at the above picture, the superheater pipes don't look too well aligned. Hmm, problems ahead.

And more gaskets to make!

Boiler Fittings (1)

Remember this item from a previous article?

Superheater feed manifold

What about this one? Possibly a more recognisable item depending on how well you've been following my 'blog exploits in the past.

Regulator Assembly in place (before restoration in December 2004)

The first is the four-way manifold used to feed the boiler's wet steam output to the four-ring superheater input; the second is the regulator assembly which receives the output from the superheater.

I showed the fitting of the superheater in a previous article confidently assuming that it could stay put from then on as in the photo below.

Superheater assembly neatly sitting in the top of the boiler

How naive!

What I hadn't spotted was that, with 2" studs sticking upwards from the manifold and regulator assembly, there was no way that these could be fitted on to the horizontal studs on the boiler without lifting the superheater about 3".

The only lifting gear at Midsomer Norton is a road-railer but it has not been available for some time. So ingenuity was going to be required.

Temporary Aerial convergent 'plate-way' in use!

I knew I could lay my hands on a jack and a lorry strap and that the superheater weighed about a quarter of a ton. After a few checks, I found my trolley jack was rated at 1.8 tons and the lorry strap at 3 tons so all was well within safe limits.

So it was a simple matter of putting the plate-way (point rods) in place to support the jack, tighten the straps and jack up the superheater. It worked like a dream!

Precise lifting ability

The jack is ideal for this as it can lift the superheater precisely to the right height and then lower it on to wooden beams for longer term support. Not wise to depend on the strap (particularly as it would get in the way of keeping out the rain!).

Interim resting place
Superheater rings showing below the top plate

So far, so good I thought until I tried to fit the manifold.

When the boiler was refurbished, all the studs were renewed. Of course, the new studs protrude precisely at right angles to the curved surface of the boiler - which means that they are not parallel! They are further apart at their outer ends than at the boiler surface and hence wouldn't mate with the holes in the manifold flange.

Five brand new studs for the manifold fixing
(there is a blanking plate fitted in the photo for a hydraulic test - I guess it had bigger holes!)

I've got a few options: bash it hard enough to make it fit (don't like that); grind the edges or ends of the studs or bend the studs so they are parallel (maybe); drill out the holes in the manifold flange (not keen on that). I'm still thinking about this!

More to come when the bits are in place.

Superheater Inlet Manifold (No Leek here (yet)!)

With the arrival of the specialised nuts, screws, washers and bolts etc., I've been able to start preparing some of the sub-assemblies for fitting.

This one is the superheater's steam inlet manifold which sits at the top front of the boiler. It takes the single boiler outlet and splits it into four for connecting to the four superheater 'rings'.

Superheater Inlet Manifold Top View (1)

The new engineering studs are a little on the long side but to no avail. They are made from EN8 which is an unalloyed medium carbon steel with good tensile strength and satisfactory for attaching a steam fitting (as you will know from a previous article on the subject!).

Superheater Inlet Manifold Top View (2)

There are two narrow-bore steam outlets, one at each side of the manifold. One of these will be used to supply the pressure gauge; the other to feed the whistle valve.

Looking from below (or it will be below when eventually mounted on the boiler), there is a spare steam outlet which has not previously been used and has merely been blanked off as in the second picture below.

Bottom View showing spare steam outlet

Bottom View - spare steam outlet closed up

This spare boiler outlet will be ideal for supplying a vacuum braking ejector!

If you are struggling to come to terms with the spelling of the heading, click here!

Superheater Assembly Installed in Boiler

Sunday 15th April 2012 saw Sentinel 7109's superheater and boiler top-plate assembly lifted down through the cab roof and installed in its place on top of the boiler.

Before installing the assembly, a ring of ceramic rope padding was put in place where the edge of the top plate would be seated. This is to provide a seal so that when the engines 'chuff' and create a vacuum over the fire, air is drawn up through the fire instead of through the gaps at the top of the boiler.

(There is more to be figured out here due to the large gaps around the superheater piping where it passes into and out of the top plate).

White ceramic 'Rope' placed around the edge

The assembly was lowered in place and lined up front to back with the boiler's wet-steam outlet and regulator valve assembly. (Hopefully we got it the right way round!).

'Derek' taking the strain with assistance from Glyn (Photo R Williams)
(Who's the onlooker in the rather fetching orange hat?)

Down a bit (Photo R Williams)
(Who's doing the in-cab lifting?)

A Meerkat cab-roof hand signal! (Photo R Williams)

And the task was completed.

Finally at home in the boiler top

So another major milestone has been achieved after many months of preparation!

Many thanks to all who helped in the process (Trevor, Phil, Glyn, Jeff and others who I may not have spotted).