Keeping 26043 Alive BCRW "Birmingham Corrosion Rust and Wastage"
Lockdown couldn't come at a worse time....26043s engine was in a stripped down state, and as a result the crankshaft (whilst protected) was exposed to air (due to the absence of the pistons) whilst protected I would have much preferred to have been able to go up to be able to keep the engine fully protected but national rules meant this had to be kept to a minimum, 26043 was also out in the yard at the time, and the engine had to be carefully sheeted over.
During lockdown I took the decision to replace 4 of the liners with brand new ones, this was a difficult decision costing over £3k, I took the decision because based on advice from others the liners were really too far gone to continue using them, and when I learnt another group had commissioned a Spanish company to cast liners according to the original Sulzer drawings I tagged along which had the benefit of increasing the order...and reducing the cost. Those liners arrived in the UK on Monday at which point the engine rebuild will continue at pace...
In the meantime however 26043 us starting to look very tired in the paint department, the paint Is past its best, and several areas of the bodywork wanted attention, so while we were waiting for engine parts, the decision was taken to resolve these issues with a view to a repaint in the current livery, correcting several mistakes such as the incorrect font on the numbers....
This is when skeletons in the closet are found.....
Exploratory cuts are made into a problem area (boiler compartment B side) the reason for cutting here was there were 3 scars (well rust blisters) which were the cause for the investigations....the amount filler present indicates all isn't what it seems...
At this point it was found that severe water ingress under the floor has started to rot the locomotive out from the inside with the trough below the skin water to around 20% of its original thickness
Another view
a close up showing the extent of the corrosion, in the void between the trough and the outer skin
Cutting away the trough upright reveals galloping rust. What you are seeing there is the cable troughs (which are 1mm mild steel) going full circle in the circle of life and turning back to iron oxide....
Cutting further up...reveals another skeleton...historic accident damage with part of the bodyside framing badly bent by an historic side-swipe the outer trough has now been cut away for replacement and the detritus vacuumed out. The yellow cloth is an oilskin covering for the wiring loom which also carries high voltage traction motor cables.
A close up showing the extent of the impact...the frame is of I beam construction of 4mm thick steel, its not trivial....
a new I beam fabricated and welded in place to replace the distorted section, the pipe in the foreground is the cause of the corrosion....
two views of the cable trough adjacent to the area recieving attention, normally this would be covered by the engine room floor but this has been removed for inspection...and rectification. Note the hole in the top view.....its deliberate....have you ever wondered why 26s and 27s have an opening bodyside window....its because you could put a steam water crane through window to fill the water tanks the squares on the body side steel was where the water pipework bolted too....this is a the reason for the sheer amount of corrosion in this area....the pipework leaked under the floor and the water was trapped.. this wasn't corrected or addressed during the class 26s last HG repair in the mid 80s...and as result the rot just sat there quietly eating the locomotive away from the inside...
HOLY JENOLITE BATMAN....
So why is the corrosion so bad......26s are one of the oldest of the pilot scheme locomotives 26043 is this year 62 years old, however 26s like most type 2s had a design life of 25 years, and as such they were built to a price....
26s like all type 2s have cant-rail grills, the purpose of these grills is to allow filtered air into the engine room....such are is then used in the engine, and traction motor blowers....without this the engine would choke on its own oil mist (before anyone asks no 26043 doesn't have a bent chassis its odd feature of my phone camera ) anyway....those grills let water in....internally 26043 has a gutter...which takes that water away and out of the locomotive....if your gutter works properly...all is good....water escapes through several drain pipes however what you cant see if the Botton 3 or 4 inches of those pipes....
A pipe with extensive corrosion which has been leaking water into the underfloor void...note the contrast between above and blow the floor....
this has also started to attack body supports further back
tidied steel which is still sound ready for rust proofing and treating
Replacement steel awaiting welding.
The structure of the class 26s, like the 33s and 27s have a load bearing under frame....in that you could strip the body away completely with all of the internal components in place and not suffer any issue, so the frame you are seeing being repaired is not load bearing, it simply supports the body skin....contrast with a class 47 which is of stressed skin construction and a slit right down the centre of the body from the cantrail to the floor...would cause the locomotive to collapse in on itself....
the rot is pretty much confined to the outer 2 inches of the floor pan the main chassis of the locomotive is as strong as the day it was built...
if we go back to this picture the other cause of the rot is directly below the outside of the cant-rail grills, these grills are of aluminium construction, and as a result cant be welded to the steel body skin, which means they have to revited...with pot rivets, over time these rivets fail causing a crack to appear at the base of the cantrail grills and the internal louvres, this means water can run down inside of the body and collect below the floor...accelerating the rot further and because this hasn't come through the louvers themselves its not caught by the gutter.
a repaired and re-enforced body frame upright
Moving further back along the locomotive reveals more accident damage from he same sideswipe this I beam has been twisted almost 90 degrees!!! broken away from its original position allowing water past it and to pool underneath the floor.
another view of the damage note the odd chequer plate welded in to "hide" the damage.
the battery isolating switch with the cover removed revealing damage to the paint behind from flash damage when the BIS is pulled out the BIS will have to be removed so the skin can be repaired behind it.
new steel welded in and primed
A side (which is in substantially better condition) being rubbed down ready for repainting...
so we can see accident damage...and design flaws...have a big impact on how a locomotive fares throughout its life...
12 weeks and counting...until completion....
Edited by pheaton
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