Apologies to the Sentinel, but I don't know how to get to 1943 articles in your archives. All credit for this goes to the Sentinel, and I would link to the stories if I could figure it out.
Here is an abbreviated version of that story written by Dave Fishell:
The headline in a May 28, 1995 article in the Sentinel was, "Boxcar explosion may have been worse if not for yardman Johnston.
"The trouble first developed as a D&RG freight train rumbled through DeBeque Canyon, the night of June 26, 1943. As the train traveled west, witnesses spotted smoke coming from the bottom of one boxcar. By 1:45 a.m. Sunday, June 27, when the train pulled into the railroad yard near the Grand Junction station, more than smoke was visible underneath two cars. Small tongues of flame were also sprouting out. And when the railroad crew learned the two burning cars were loaded with 20mm artillery shells headed for the war front in the Pacific, the cars were quickly detached from the train and pulled away towards the west end of Main Street.
Even though the Grand Junction Fire Department responded to the call, there wasn't much the fire fighters could do. As flames raced through the two boxcars, more and more shells detonated, spraying much of the downtown area with hot, flying fragments of metal munition.
Firefighters, police officers and railroaders all wisely sought cover or tried to keep the increasing crowd of spectators back away from the bombardment.
It took hours for the thousands of shells to blow up. All night long shrapnel whistled overhead. Lots of the fragments burrowed into nearby roads and sidewalks. (Every once in awhile an old piece of shell is uncovered yet today). Some of the hunks of fiery metal tore through roofs, walls, doors and windows. Numerous vehicles were also riddled by shards of the exploding artillery shells.
Finally, by early Sunday morning, the shells were spent. All that remained were the wrecked hulks of the two boxcars, twisted and torn almost beyond recognition by the force of the exploding shells and the tremendous heat.
By far the most serious accident occurred when a fragment of artillery shell cut through Fire Chief Charles Downing's upper right arm. The arm was later amputated... another shell fractured Bob Walraven's jaw... Mrs. Virginia Buckley suffered a broken arm "and numerous cuts."
Fifty-one years after the boxcar attack, I was sitting next to Johnston's bed.
(Konola note: The story then goes to the next page, where the headline was "Explosion: Gas could have caused bigger problem")
Johnston... started talking in a low voice.
"I'd only been working for the Rio Grande for just about a year, and I was a yardman on duty when those cars caught fire ... And I don't think anybody knows what could have happened that night.
"Since I was working the yard, I had the consist (or shipping list), and when that train rolled in with those two burning cars, I realized from the consist that most of the other cars in that train were also carrying ammunition. I don't know if it was all big shells--the consist didn't say--but there was lots more ammo on board.
"And just two tracks away sat about 75 tank cars all filled with gasoline. Since I had the consist, nobody else knew what was over in those cars.
"That's when I decided those two burning cars had to be moved. Who knows what would have happened if the ammunition or the tank cars also went up?"
... as far as I could tell, nobody ever gave credit to the man who gave the orders to move the two cars, the only man who knew downtown Grand Junction and thousands of residents were in much more danger than anyone realized.
(Konola comment: The story then goes on to talk about a conversation with then administrative fire official Bob Keeling)
"In a situation like that it's not impossible to get a rupture in a tank car, then the car and gasoline would just burn, but the cars probably would not explode" said Keeling. "A bigger hazard is with the external heating on a tank car. Today, our training calls for cooling the cars so the steel doesn't soften. If external heat gets to the point where steel starts to soften, then you have a bigger problem."
If those two exploding boxcars hadn't been moved that night in 1943; if the rest of the ammunition train had caught on fire; and if the fire had become hot enough to affect the steel on 75 tank cars filled with gasoline, my guess is downtown Grand Junction would indeed have had a "lot bigger problem."