| Photos (11th
August 2005): Tony Wood
| 27th
July 2005:
Big-ends Martin
wrote (see below) so here are photos of Bittern's
middle big-end taken today to show the parts being discussed.
This strap is made in one piece. I'm told the failure on Green
Arrow was at the base of the bit that looks like a stud. The
rest of the strap bent and the rod came away from the crank-pin. I
imagine the piston would then act like a rather powerful steam hammer
until something broke. Removing this big-end strap
for inspection would indeed be a pain, as you have to separately
support the weight of rod and strap. When you have removed nuts and
washers the big-end won't come apart easily; when it does, the brasses
will want to fall out. |  |
Gresley locos: middle big ends
Hi Tony
I think it might be of interest to many of us if you and your fellow
experts at the Ropley Centre of Excellence could
enlighten us on this subject.
The reason for my question is
that, as you may have heard, V2 LNER # 4771 Green Arrow recently
suffered a serious failure while running on the main line between
Scarborough and York. I don't know the precise details but it was
something involving a complete failure of the middle big end, and has
caused rather expensive damage to the inside cylinder as well as to the
big end itself.
I saw it stated in a newsgroup that the
design and construction of the middle big end on Green Arrow is
such that the inspections and tests needed to give warning of a likely
failure cannot be carried out without major dismantling, and that it is
not practicable to do this before every main line run.
What
was more worrying was a statement that other Gresley 3-cyl engines also
have the same design of middle big end as Green Arrow.
So while you have Bittern in the shed
being reassembled, would it be possible for you to show us some
pictures of what is involved here?
Thanks
Martin 26 July 2005 09:44 |
 |  |  | All
critical components of course get non-destructive testing at Ropley
(ultrasound, magnetic particle inspection, etc.) before being passed
for assembly Note that the brasses shown are Bittern's
originals; they will be replaced with new ones made and white-metalled
in-house |
 | New
grate fingers Bubs
was milling square ends on
some valve-spindles for Bittern's boiler fittings, but there wasn't a
good photo in it that I could see ... tw Photos
(all 27th July 2005): Tony Wood |
| 8th
July 2005: Bittern's
valvegear has been fitted Photo (8th July 2005): Ray
Sully |  |
 | 3rd
August 2005:
Valves for Bittern
|
| Andy was welding-up new superheater
elements Movie
(1.2MB) Four
photos and two movies (all 3rd August 2005): Tony Wood |
 |
 | 21st
July 2005:
Andy showed me the fittings on Bittern's boiler ... |
| ... and Spud was busy trueing the
new mud-hole doors. In the machine shop, Neil was machining
the newly white-metalled axleboxes, so Bittern will
be on all its wheels ready for the boiler to be installed.
Three photos (all 21st July 2005): Tony Wood |
 |
| 27th
June 2005:
The chimney is back from repair
Also
Also Three
photos (27th June 2005): Ray Sully |  |
| 22nd
June 2005:
Light reflects from prepared faces of flanges for
boiler fittings ... |  |
 | ...
and boiler plugs
Photos
(22nd June 2005): Tony Wood
|
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