The Locomotive 704 Boiler: Threw 16,000 Pounds of Steel 1,200 Feet and Killed 26 in Texas
Steel & Sacrifice
41,538 views
Locomotive 704 was a ten-wheel steam engine, roughly 200,000 pounds of steel and iron built to haul heavy freight over long distances. On December 18, 1911, it was wrecked near Seguin, Texas, badly enough to take it out of service for months. It went to the Southern Pacific roundhouse on North Hackberry Street in San Antonio, where skilled tradesmen worked it over for weeks. The repairs were finished on March 17, 1912. The next morning it sat outside the roundhouse waiting on its mandatory steam test — the routine final checkpoint before returning to the line.
To every man in that yard it looked like exactly what it was: a finished job, resting. Heavy, still, done. That stillness was the problem. A locomotive at pressure is not a machine at rest. It is a vessel holding superheated water in violent equilibrium — water heated well past its normal boiling point and kept liquid only by the containment around it. Break that containment and one cubic inch of it becomes roughly sixteen hundred cubic inches of steam faster than any unit of time a person uses.
The only guaranteed escape route for excess pressure is the safety valve: a spring-loaded valve seated against a port in the boiler shell, set to lift at a defined limit. The set point is governed by an adjusting screw. Turn it one way and the valve opens sooner. Turn it the other and it holds longer, requiring more pressure before it will vent, and the safety margin quietly shrinks. From outside the boiler, nothing about that threshold is visible.
At 8:55 a.m. on March 18, 1912, the shell tore. A section of boiler estimated at roughly 16,000 pounds — about four full-sized pickup trucks — was thrown some 1,200 feet. The boiler head, around 1,250 pounds, went about 1,200 feet the other way. Engineer Walter Jourdan and shop painter José Fuentes were killed instantly. The overpressure wave demolished buildings within about a hundred feet and collapsed adjacent railroad shops onto men who had no connection to the locomotive at all. Reported deaths range from 26 to 40. That range is itself a finding: the disaster destroyed the spaces some of its victims were standing in, and the record never closed the count.
A public board of inquiry opened within days, then transferred to the Interstate Commerce Commission on March 22 for closed-session investigation. The report came out May 17, 1912. The cause was excessive steam pressure, resulting from an employee of the Galveston, Harrisburg and San Antonio Railway tightening the adjusting screw of the safety valves. Not a flaw in the steel. Not a bad weld. A screw, turned by a hand.
This documentary tells the story of a safeguard that wasn't ignored or forgotten or rusted shut. It was given deliberate, careful attention — by someone focused on the wrong variable, inside a system that made that mistake easy to make.
🔔 SUBSCRIBE if you value the forgotten stories of those who built our modern world — and want to keep their history alive.
Real human narration is used in this video. Portions of this video contain edited or simulated visuals for illustrative purposes.
Disclaimer: The pictures and clips used in the videos on this channel are a mix of illustration, royalty-free, public domain, or otherwise fall under the guidelines of fair use. No copyright infringement is intended. All rights belong to their respective owners.
12 Comments
Also someone should have been watching the pressure gauge and when it reached no more than 1 lb over maximum boiler pressure the valve should have let go, obviously it didn't and that should have been immediate manually release the valve or shut the fire off at a minimum
The loco had just been overhauled. Obviously safety tests were skipped. Safety procedures ignored. This loco became a bomb.
The loco design itself should have had more than 1 safety release. In particular a built-in blowout plug. The existing design was prone to human error.
Since this was the 1st time loco was pressurized after rebuild, why wasn't an operator monitoring the pressure gauge?
To make headlines that make history, a lot of negligence is present. We had been using steam power for a century. It was nothing new.
Retired in Sacto
The Locomotive 704 Boiler: Threw 16,000 Pounds of Steel 1,200 Feet and Killed 26 in Texas
Steel & Sacrifice
41,538 views
Locomotive 704 was a ten-wheel steam engine, roughly 200,000 pounds of steel and iron built to haul heavy freight over long distances. On December 18, 1911, it was wrecked near Seguin, Texas, badly enough to take it out of service for months. It went to the Southern Pacific roundhouse on North Hackberry Street in San Antonio, where skilled tradesmen worked it over for weeks. The repairs were finished on March 17, 1912. The next morning it sat outside the roundhouse waiting on its mandatory steam test — the routine final checkpoint before returning to the line.
To every man in that yard it looked like exactly what it was: a finished job, resting. Heavy, still, done. That stillness was the problem. A locomotive at pressure is not a machine at rest. It is a vessel holding superheated water in violent equilibrium — water heated well past its normal boiling point and kept liquid only by the containment around it. Break that containment and one cubic inch of it becomes roughly sixteen hundred cubic inches of steam faster than any unit of time a person uses.
The only guaranteed escape route for excess pressure is the safety valve: a spring-loaded valve seated against a port in the boiler shell, set to lift at a defined limit. The set point is governed by an adjusting screw. Turn it one way and the valve opens sooner. Turn it the other and it holds longer, requiring more pressure before it will vent, and the safety margin quietly shrinks. From outside the boiler, nothing about that threshold is visible.
At 8:55 a.m. on March 18, 1912, the shell tore. A section of boiler estimated at roughly 16,000 pounds — about four full-sized pickup trucks — was thrown some 1,200 feet. The boiler head, around 1,250 pounds, went about 1,200 feet the other way. Engineer Walter Jourdan and shop painter José Fuentes were killed instantly. The overpressure wave demolished buildings within about a hundred feet and collapsed adjacent railroad shops onto men who had no connection to the locomotive at all. Reported deaths range from 26 to 40. That range is itself a finding: the disaster destroyed the spaces some of its victims were standing in, and the record never closed the count.
A public board of inquiry opened within days, then transferred to the Interstate Commerce Commission on March 22 for closed-session investigation. The report came out May 17, 1912. The cause was excessive steam pressure, resulting from an employee of the Galveston, Harrisburg and San Antonio Railway tightening the adjusting screw of the safety valves. Not a flaw in the steel. Not a bad weld. A screw, turned by a hand.
This documentary tells the story of a safeguard that wasn't ignored or forgotten or rusted shut. It was given deliberate, careful attention — by someone focused on the wrong variable, inside a system that made that mistake easy to make.
🔔 SUBSCRIBE if you value the forgotten stories of those who built our modern world — and want to keep their history alive.
Real human narration is used in this video. Portions of this video contain edited or simulated visuals for illustrative purposes.
Disclaimer: The pictures and clips used in the videos on this channel are a mix of illustration, royalty-free, public domain, or otherwise fall under the guidelines of fair use. No copyright infringement is intended. All rights belong to their respective owners.