Steam Train strafed by aircraft in WW2

[FatboyCoxy]

Hi all

I've seen a number YouTube video's of German steam trains being strafed by Allied aircraft in WW2. They often finish with a catastrophic explosion. Did this happen to all steam trains that were hit, or could they be damaged, and not explode?

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It depends on what they were hit by. Machine gun rounds could pass straight through a loco boiler, it would create an enormous escape of steam, it might cause the boiler to burst. If the aircraft fired a cannon shell it would explode on impact.

[Bigmet]

Any rupture of the boiler shell (pressure vessel) typically results in a destructive explosion, as the damage caused by the penetrating projectile leaves cracks in the steel boiler plate, which very rapidly propagate in the escape of the steam and boiling water, detaching pieces of plate, and the boiler tubes deforming in the escape. This typically required a 20mm cannon shell or a larger munition (allied aircraft machine guns would only reliably penetrate rather ancient boilers, a modern locomotive of that time would be very unfortunate to have its boiler ruptured by such) .

[Journeyman]

During the ll WW the North Pembrokeshire line was extensively used by both the RAF and the USAF to evaluate the use of weapons. One thing they did was to bring an LNER Locomotive No 1241 to Puncheston paint it white and use it for target practice.
Then in June1944 they used an Aberdare class 2-6-0 No 2656 parked between Rosebush and Puncheston which was attacked by USAF Fighter Aircraft using cannon and machine guns, they scored 35 hits. Subsequently the engine was repaired and returned to traffic.
This is the same line that Barnes Wallis used in 1943 to practice using tunnel bombs designed to destroy the V1 flying bombs in their tunnels. The 618 Mosquitoes squadron used the Maenclhog tunnel to test out the bomb sights with some success.

Dave.

[Bigmet]

During the ll WW the North Pembrokeshire line was extensively used by both the RAF and the USAF to evaluate the use of weapons. One thing they did was to bring an LNER Locomotive No 1241 to Puncheston paint it white and use it for target practice.
Then in June 1944 they used an Aberdare class 2-6-0 No 2656 parked between Rosebush and Puncheston which was attacked by USAF Fighter Aircraft using cannon and machine guns, they scored 35 hits...

That sounds like the source of the information I recall.

The British 303 (rifle ammunition) aircraft machine gun wouldn't do the job, unsurprising as the loco boiler was necessarily built to much the same standard as applied to pre-war tank designs, and armoured cars throughout that war. And of course the loco boiler typically had an outer cladding, and two inches of insulation, before the pressure vessel was reached and most of the target was oblique to the projectile trajectory, equivalent to 'sloped armour'.

The American 0.5" aircraft machine gun was much superior, but still not a large enough projectile to be reliable.

The move to the 20mm cannon was what was required, firing a mix of solid, HE and tracer rounds. Or alternatively and even better the RP3 ('60lb') air to ground rockets, a single strike pretty much anywhere on a locomotive was sufficient to immediately disable it, even if the boiler was undamaged.

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Post WW2 my fathers employers were looking to expand into the automotive and small ic engine fields, there was a money available for new facilities if they would also provide a home for and personnel to operate an automated cannon shell production line. It was fed with steel discs and spat out empty shell cases which I think were 48mm. When it was first mothballed then dismantled I acquired a number of trophies, a fully finished shell case, a dummy detonator and a dummy charge, plus a reel of 8mm filmstock which had been used for training purposes. When I finally managed to find someone with an 8mm projector it turned out to show target practice firing at steel mine tub wagons which were rolled down an incline and any that survived were pulled back up by a tractor which straddled the NG track. It was notable that a direct hit with one of those shells reduced the wagon to shrapnel which was cleared up between sessions by the tractor carrying a large electromagnet on its front tines. I never did find out where the firing took place and I eventually passed on the collection to the father of a friend who was the officer IC the local home guard/civil defence depot. He was delighted to get it as "THEY never let us have anything interesting like this".

[Journeyman]

That sounds like the source of the information I recall.

The British 303 (rifle ammunition) aircraft machine gun wouldn't do the job, unsurprising as the loco boiler was necessarily built to much the same standard as applied to pre-war tank designs, and armoured cars throughout that war. And of course the loco boiler typically had an outer cladding, and two inches of insulation, before the pressure vessel was reached and most of the target was oblique to the projectile trajectory, equivalent to 'sloped armour'.

The American 0.5" aircraft machine gun was much superior, but still not a large enough projectile to be reliable.

The move to the 20mm cannon was what was required, firing a mix of solid, HE and tracer rounds. Or alternatively and even better the RP3 ('60lb') air to ground rockets, a single strike pretty much anywhere on a locomotive was sufficient to immediately disable it, even if the boiler was undamaged.

Hi Bigmet,
That account came from “The Railways of Pembrokeshire” Chapter16. They actually have wrong information about why they where bombing the tunnel so I corrected that in my account. One thing the line was kept running throughout the weapons testing with the gangers repairing the line and tunnel portal overnight. You can still see the gouges out of the brickwork today. Never mind about leaves on the line this was (wooden) bombs on the line!