Just saw some photos of the explosion of SP 704 in 1912 in San Antonio, TX.

Official cause was low water....

The photos show the apparent epicenter of the blast to be confined to the area of the boiler barrel adjacent to the #3 driving axle.

The force bent the frames outward; blew the driving wheels off of #3 axle and caused considerable loss of life.

I find nothing on this site about the event.

Thanks for looking!

Paul J. Ferry

The story I heard was that this accident occurred during a strike. Supposedly a strikebreaker with very little RR experience was setting the safety valves, and he failed to notice that the steam gauge had already gone completely around, and the needle was pushed up against the back side of the peg. He thought he had zero psi, and kept firing the engine, trying to raise pressure, which eventually caused a shell failure at extremely high pressure.

The story about low water was said to be a cover up. I don't really know. I wasn't there.

There is an ICC report about this incident. As I recall, the inexperienced mechanic working by himself trying to set the pops was a contributing factor, along with the syphon from the boiler to the gauge having two shut off cocks, one open when the handle was in line with the pipe, and the other open when the handle was crossways, and one of those was closed.

Witnesses said that the blower was running hard for 45 minutes. The investigation found that both pop valves were screwed down until the springs were collapsed solid.

Some crown bars were pulled apart. Investigators tensile tested the intact crown bars and from the strength found in those, extrapolated that the boiler pressure could have been as high as 600 PSI.

For those that haven't figured it out yet, the conclusion is that with the pressure gauge shut off, the mechanic kept firing the boiler to raise the pressure, which wasn't happening. But the pops kept lifting, so he kept screwing them down until the boiler literally failed. Some supervision at this point would have helped.

The result of this incident was the prohibition on having more than one valve between the pressure gauge and the boiler, and the requirement for a second pressure gauge mounted next to the pop valves when they are being set. It's a good idea to do this work with a helper.

Thanks everyone; didn't think it looked like a crown failure as bad as they are

PJF

A relative of mine was killed in this explosion. I never did hear any facts about the incident aside from the fact that he was in the roundhouse, getting ready for his run when the boiler popped. It's cool to learn some actual details about the incident. Thanks for sharing this!

Zack,

Sorry for you to have a personal connection.

I did find a list of the victims; you can probably find his name.

Paul

Reading the article link in this post is interesting. I know union strikers can do all kinds of bad tricks. My Uncle Bill ( William Godfrey Hovel , now that is a name ) was a railroad detective for AT&SF in the 1920'as and 30's . There was all kinds of union sabotage going on in those days. He died in 1972, had lots of stories, left the railroad to join the Los Angeles Police Department. Now there was another extremely corrupt organization till 1938-46.

Even though we we were ranchers my Dad had a security agency that provided service to business involved in the early space programs of the 1950's and 60's. He had to deal with a lot of union strikers sabotaging in the industry including the night union thugs attacked our house and tried to set it on fire.

Anyone with any mechanical skill or concepts would not screw down or lock down pressure relief valve, which were not already escaping steam, to increase boiler pressure. I know of one commercial certified boiler engineer, running his own locomotive, sets his first minor relief vale short or below the second or major valve. Listens to hear the first one start to leak off on warm up. After 50 years I guess he knows what he is doing, me I am only ignorant.

Would be very conceivable for someone to tamper with the loco in the middle of the night, knowing the pressure to get it back in service and the lack of familiarity with the "scab" workers with the unit. Depending on a defective gauge and tampered pressure relief valves. Having to carry a gun in the shop to fend off union attack or tampering. Hmmm. Could a pressure gauge that had say a maximum pressure indicating range of 300 psi, not rupture at 350 psi first, certainly giving some warning ? Would it alone run to 600 PSI ?

Any public account of union tampering would cause more business damage to the RR than boiler failure. Union tampering would scare off customer base and reduce faith in equipment safety.

Just an opinion.

.

Do you happen to have a link to said list? A cursory Google search didn't yield any results. Does it list injured personnel as well? I seemed to recall my grandmother saying that the relative was injured, but when I mentioned it to my dad this evening, he said that he thought said relative was just severely injured and was able to retire early because of the incident.

As reported in April, 1912 in "The Locomotive," published by the Hartford Steam Boiler Insepction and Insurance Company.

https://archive.org/details/locomotivev ... ew=theater

Thanks to everyone that's responded.

The Hartford Boiler, with whom I've worked, report is very enlightening; look at the accident list by month!! Can you believe it!

I didn't know the loco was an oil burner which creates some questions:

-Start at appox.200psi.

-Steam raises to an estimated 600psi.

-Unless adjustments are made to the atomizer or oil valve, the flame should have
blown out at the higher pressure as my experience with oil firing.

Paul