March 2010 Progress report
article by: John McMillan
After all the excitement of steaming the boiler last November,
Chatham Steam still had some big jobs to do before the boiler could
return to Toddington. They had to install the super heater
header and elements in the boiler and hydraulically test the joints
- this job was completed just before the 'Big Freeze', and the
boiler was drained and dried out even as the thermometer
plunged!
Another major task was making the Combine Pipe - this runs along
the top of the firebox in two planes and connects the steam
manifold in the cab to the emergency shut-off valve on the firebox
shoulder (it's that mysterious wheel valve on the driver's
side). Chatham Steam skilfully completed it in one piece,
which eliminates possible leaking joints. By filling a
straight pipe with sand to stop it collapsing whilst bending, they
formed the complex shape by a combination of heat and hydraulic
bending equipment. We had previously fitted the crinolines to
the firebox so the required alignment of the pipe could be seen,
and the shut-off valve was fitted to the boiler. It took a lot of
"trial fits" before the alignment of the pipe was correct.
The remaining major job at Detling was to fit the mechanism that
operates the regulator valve in the dome. A long rod was
threaded through the boiler back head, along the top of the inner
firebox to the regulator valve, to which it was attached by a
pin. On the back head the stuffing box, cross shaft, bracket
and regulator handle were all fitted up. It took a number of
adjustments to the alignment of the whole assembly before
everything operated freely when the regulator handle was given a
tug.
Back at Toddington, winter work on the loco chassis concentrated
on the essential jobs necessary before the boiler could be replaced
in its frames, the key task being to complete the repairs to the
rear left hand pad that takes a good deal of the weight at the back
of the boiler. A manganese strip was welded on using special
welding rods, then the pad was attached to the chassis using fitted
bolts. We also managed to do a few tasks that were easier to
undertake whilst the boiler was out of the way. These
included needle-gunning and repainting parts of the frames where
the paint was looking tired.
We have also reinforced the left hand running boards where the
brackets for the injector delivery and steam heat pipes are
located; the opportunity was taken to paint the undersides of the
boards before they were re-fitted. The drive links to the
right hand side lubricators have been fitted up and checked to
ensure they operate freely. The drive is taken from the
expansion link, and it's quite satisfying to rock the link to and
fro by hand and watch the lubricators nodding gently in
response.
On the tender, the twelve brake hanger arms have been fitted
with brake block holders, brake blocks and tensioners. Each
assembly was lifted into place using a car trolley jack.
Making up the handbrake shaft for the tender has proved more
challenging!
The locomotive valve gear has received some attention recently,
and work has continued on the task of fitting the valve rods with
new bearing bushes, about one third of which have now been dealt
with. We're not that far off being able to offer a set of
valve gear up to the loco to check that everything moves
freely.
After two and a half years in Kent, the boiler was finally
craned back into its frames at Toddington on the 24th
February - rather later than the "nine to twelve months" originally
predicted! The boiler lift went very smoothly; the weather
was fine, we used two cranes again to control the 30-ton boiler
more securely, and the boiler was lowered to a point only about
1/8" off the centre line - one crane driver said he normally works
to an accuracy of six inches! The boiler sits on blocks in
the frames so the cladding can be re-fitted round the barrel and
throat plate, then it will be lowered to its final position using
jacks.
Within days of its return the locomotive was shunted under
cover, and we can now get on with the long business of assembling a
multitude of parts. We don't yet have all the money we'll need to
employ specialist contractors along with our volunteer workforce,
so if you'd like to help us to complete this project, please get in
touch via the website or through Toddington. However, we can
say that the light at the end of a very long tunnel is glowing a
bit brighter!