Wednesday, 24 February 2016

Testing Times (1)

Tuesday 23rd February 2016 was an important day - the day an inspector called. In this case Peter Hawkins the boiler inspector.

It had been a busy few weeks leading up to this but essential to be ready for action on the S&D 50th anniversary of the line closure on March 6th 1966.

There were various tests: A general inspection of paperwork covering materials used, certificates of conformity and calibration; a hydraulic test to 1.5x working pressure (412.5 psi) to check boiler fittings were attached properly; a maxed-out steam accumulation test to abuse the boiler and check the safety valves could cope; a test of the ability to keep the boiler filled with water under maximum output conditions.

Giving the clouds a shock!
If you are wondering what Sentinel 7109 sounds like when being steam tested, try this video clip: (Higher def. on YouTube)
We also tried a less formal haulage test on the 1 in 53 gradient as in the following video clip (Higher def. on YouTube):
There are interesting times ahead!

(And it passed the tests too!).

Thursday, 18 February 2016

Rebirth of 7109!

Blessed with brilliant cool and bright weather, Thursday 18th February 2016 was the beginning of a new life for Sentinel 7109 when she emerged from the shed at Midsomer Norton station 56 years after her retirement at Croydon Gas works in 1960.
This video clip says it all (Better resolution on YouTube).

The 'beeps' in the background are the shed's smoke alarms giving their salute!
Back into life
A picture speaks louder than words.

Tuesday, 16 February 2016

Chained Malady!

Just to complete my last article about enchaining Sentinel 7109, here is the new view beneath the frames looking from the front.
Drive chains in place
It's not clear from this photo that the chain on the right (of the photo) is slacker than the other. Despite very careful setting up of the axles and even more thoroughly checking that the chains were actually the same length, one chain insists on drooping. At present, I don't know the cause of this although I expect they will equalise with running in.

I also previously referred to items called chain 'slippers' and these are in the photo below.
Chain 'Slippers'
Whether these resemble Sentinel's idea of a chain slipper, I don't know; however, they did the job required of them.

Friday, 12 February 2016

Unchained Malady!

The last time I wrote about chains was in January 2012. That was to do with renovations, now it's time to actually fit them to Sentinel 7109.

After some discussion, I concluded that to fit these heavy items safely in an awkward situation was not going to be easy and required the preparation of some special tools to assist. It was going to be quite a complicated process to be able to get the chains into position mid-way between the sprockets and then get the chains over the sprocket teeth so that the two ends could be joined.

The first tool is a trolley to carry the chain under the loco.
Chain trolley
The centre of the chain is placed in the centre of the trolley with each end piled up to allow it to be pulled over its respective sprocket.
Trolley with chain in position
The trolley and chain are then put on a plank to wheel the chain into position. The upright support piece of wood is to prevent the trolley drifting off the plank and on to my lap whilst underneath!
Ready to go under
The next tool is, as Sentinel called it, a chain 'slipper' to allow the chain to be dragged over the sprocket teeth. One is needed for each sprocket.
Chain 'slippers' in place
I made the slippers from Aluminium strip left over from another job. I drilled a hole at each end and put in a bolt and nut to enable a strap to pull the ends together.
Axle sprocket with slipper
For the second slipper, I used two bolts so that a ratchet strap could be used to tighten the slipper with static straps to hold it once tight (I only have two ratchet straps so limited resources!).
Ratchet & static straps on drive sprocket
The chain was then wheeled into place...
Ready to drag chain over slippers
...and dragged over the drive sprocket.
...and over
The chain was then secured to prevent it from slipping back over.
Secured from slipping back
Then the slipper was pulled out after removing the bolts from one end to allow it to pass under the chain. (It had to be pulled quite hard!).

The same process was then applied to the axle sprocket and the two ends pulled together with a light duty lorry strap.
Ends pulled together from afar...
...and from anear with both slippers removed
At this stage, I came to the conclusion that the light duty ratchet strap was not strong enough to pull the ends together and that a heavier duty type might do the trick.
This photo shows that even that was not going to solve the problem.
So near yet so far!
I had assumed all along that the axles would be in the same position as when the chains were removed. However, clearly that is not the case and the axles and brakes will all have to be adjusted to get the sprockets the right distance apart for the chains to fit with the correct tension (+/- 2" movement mid way between sprockets).

Tuesday, 9 February 2016


48 years since Sentinel 7109 was last believed to have been steamed (and 56 since it was definitely known to have been steamed), finally a fire has been lit in the grate of this unique double-engined Sentinel locomotive.
Steam rising

An early start on Tuesday 9th Feb. 2016 saw Andy Chapman, Nigel Dickinson and Graham Findlay (with a cameo appearance from Justin Goold) applying the match at 08:30am.
Oily rag activity
Activity began slowly.
Slow start
A whimper from the rooftop:
Fumes fuelled the fire
Raging inferno in the making
With commensurate reaction from above.
Quadruple chimneys' worth
And more fuel for the fire.
A handful of coal
With more reaction from above.
Close atmosphere developing
Not such a cold day after all.
A nice fire to sit by
But getting a little foggy inside!
A real pea-souper!

Inevitably a new machine brings its own noises. The cab-mounted Worthington-Simpson steam driven water pump gets some exercise - what a wonderful sound! (Also on YouTube).

A brilliant day of progress and a joy to see and hear 7109 coming back to life with enthusiasm!

Note: water hoses and fire extinguishers were close at hand during the whole operation.

Sunday, 7 February 2016

How to fit an Ashpan (8)

I last wrote about Sentinel 7109's ashpan in December 2012. In that article, I showed the fixing brackets being processed. Since then, the whole ashpan has been languishing in my garage acting partly as a storage shelf and partly just getting in the way!

February 7th 2016, three years later, it is now actually fitted to the loco (bar a few missing nuts).
In place beneath the boiler
This photo shows how it was originally - not so different!
The original (other side view) 
There is a flap for raking out the ash.
Open for emptying
It can be closed when 7109 is in use.
Closed for use
Whether the flap is also for use as a fire-controlling damper, I don't know. I need to do some more reading on the subject.

I made a small change before the fitting in that I replaced the flap hinges with stainless steel ones. The previous mild steel ones struck me as incapable of withstanding the nasty environment.

In another Ashpan article, I showed the ashpan being jacked into place. At the time, 7109 was outside with track and sleeper ballast underneath. It was not an easy working environment.

In Midsomer Norton's shed, the floor is flat and can be traversed under 7109 using a creeper trolley. This enabled me to lie on my back with the ashpan sitting on my chest. I could then lift it into place and hold it there using a spare leg whilst doing up the nuts. Fortunately I was unable to take any photos of the process. Sometimes a selfie is just out of place for a situation!

Wednesday, 3 February 2016

Certified Gauges

Perhaps not a particularly gripping subject but important all the same. Sentinel 7109 has two steam pressure gauges and a vacuum brake system vacuum gauge; all of these are 'previously owned' and far from new.

All three gauges were initially taken to Brunel Metrology Services Ltd in Paulton, near to Midsomer Norton. The vacuum gauge passed first time but the two pressure gauges failed - not what was wanted but not surprising for vintage items.

Brunel Metrology make use of the S M Gauge Company in Fishponds, Bristol, for more demanding calibration tasks. To save time, I took the two gauges to SMG myself.

In a few working days, a phone call came to say the gauges were now calibrated to within 1% so I collected them the same day.
Within 1%!
Calibration certificates have now been issued for all the gauges and one is shown here as an example.

It was a pleasure to work with both Brunel and S M Gauges and I would recommend either for gauge calibration services. Many thanks to them both for their helpfulness and rapid turnaround.
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