“I should think they would have them all of steel!” gasped Bluff, as he labored away, passing endless buckets up and down.

“Most of them are, I understand, but in this case, you see, it is a long stretch, and perhaps it wasn’t thought necessary,” replied Frank.

“We’re going to save it, all right; but I wonder if our train dare pass over?  It seems to me the fire must have weakened the structure more or less,” remarked Jerry.

“Oh, well, they’ll find some means of strengthening it in that case.  I’m only worrying about the delay.  Mr. Mabie will have to wait so long.”

“But, Frank, they must wire the news, and he will know the reason for our hold-up,” said Will quickly, and the others all agreed that this must be so.

Less than an hour later the last spark had been extinguished.  Then men climbed all over the trestle to ascertain just how much it had been weakened by the fire.

There was a difference of opinion among them, some declaring that it was as good as ever, and the others shaking their heads solemnly, as they prophesied all manner of dire things if the through train, with its heavy sleepers, attempted to go over.

While some gangs of men were hastily bracing up a weak spot with what material lay close at hand, kept for an emergency of this sort, a freight train that happened to be on a siding at the station, was pushed out on the trestle to discover how the situation stood.

The chums watched operations with their hearts in their mouths, figuratively speaking; but no catastrophe followed, and it began to appear that, after all, the express might pass over in safety.

Another trial was given, this time with the heavy freight engine attached to some of the largest flats, laden with steel beams.  The trestle bore the strain handsomely.

“That settles it, fellows.  Back to our car for us.  We’re going across!” sang out Jerry as he turned and made off down the track.

“How long were we here?” asked Bluff, sighing, and they knew he was thinking again of the weary hours that must elapse ere he could open that big trunk in order to ascertain whether his fears in connection with that beloved hunting-knife had any foundation or not.

“Three hours, about.  Give them another half hour to get moving, and there you are.  Hark!  The engineer has started to whistle.  That is to tell the passengers a start is intended; and here they come, rushing pell-mell, fearful of getting left.”  And Frank laughed at the energy displayed by some of those who had been aboard.

It was a critical time when the train slowly pushed out upon the long trestle.  Everybody doubtless held their breath, and doubtless many a heart throbbed with suspense.

“It’s all right, boys!  We’re safely over!” exclaimed Jerry, as, looking out of the open window, he could see that they had passed the critical stage.

“Oh!  I’m so glad!  I don’t know when I’ve felt such a flutter about my heart.  But, anyway, I secured a cracking good snapshot of that burning bridge.  Every time we look at it we can remember our hold-up,” observed Will, sighing with relief.