Learning from the Tragic Accident in Medina

The downward force of the blast lifted the steam traction engine (weighing approximately 40,000 pounds) upward from the surface of the ground approximately 10 feet into an adjacent tree. With the flywheel being on the right side of the engine, along with the probable shifting of the water in the storage tanks, the tractor tipped to the right on the way down. Upon landing, the right rear wheel snapped from the axle, the front pedestal also broke and folded the right front wheel under the boiler.

Observations:

Upon further inspection of the steam traction engine on July 31, 2001 and August 7, 2001 the following conditions were observed:

• Metal fatigue was noted in isolated areas on the waterside of the crown sheet (test report submitted by Case Western Reserve University).
• Areas of crown sheet appeared to have a reduction in thickness (ultrasonic measurements and calculations being reviewed).
• Crown sheet stay bolts had approximately 20 percent deterioration on their lower ends compared to their upper end thickness.
• One crown sheet stay appeared to have been broken prior to this explosion.
• A bushing had been welded in the crown sheet to hold the fusible plug.
• It appears that the position of the fusible plug was altered by the placement of the bushing.
• The length of the fusible plug appeared to be more appropriate for a Scotch Marine boiler than a Locomotive type boiler.
• Stay bolts adjacent to fusible plug were seal welded.
• Fusible plug was still intact; the center had not melted out (test report submitted by Case Western Reserve University).
• At least one hand hole had approximately 20 percent random thinning of metal compared to its overall thickness.
• It appears that the water column and gauge glass may not have been original equipment.
• Placement of water column and gauge glass in relation to the minimum water level of the boiler may be different from the originally installed position but it appears that it would have provided an acceptable working range.
• Bottom of gauge glass was cracked at the packing nut.
• Packing nuts on upper and lower gauge glass were hand tight.
• Packing nut on piston connecting rod took eight quarter turns by hand before making contact with packing.
• There were small amounts of scale found in the water legs.
• Wagon top indicated minor pitting on waterside.
• Riveted seam on crown sheet showed evidence of previous metal fatigue and some rivet heads appeared to have deteriorated approximately 25 percent based on appearance of the other rivets in the area.
• Majority of injector connections were hand tight and could be tightened or loosened without assistance of a wrench.
• The right side injector piping varied in size throughout its length to the inlet of the boiler.
• Safety valve was attached to steam dome with no external damage noted (test report submitted by National Board).
• Pressure gauge was severed from its connection on steam dome (test report submitted by National Board).
• Feed water heater piping contained numerous galvanized fittings.
• All boiler external piping appeared to be less than schedule 80.
• Drive wheels were engaged.
• Johnson bar was back, indicating a possible forward movement.
• Steam draft was approximately 1/4 turn open.
• Cylinder drain cocks were open.
• Left injector was lined up to take on water (test report submitted by National Board).
• Right injector was secured from operation (test report submitted by National Board).