The young fireman was soon headed for the railroad yards.  A good many people were bound hurriedly in the same direction, for the explosion had aroused the town.

As he neared the place, he could hear considerable shouting.  He came to the tracks at a point where there was a switch shanty.  The man on duty looked worried and scared.

“What is the trouble?” inquired Ralph.

“The strikers have blown up a freight car with dynamite,” replied the flagman.  “They have threatened me, old and feeble as I am.  I’m afraid I’ll have to lay off till this trouble is over.”

In the distance Ralph saw the mere skeleton of a freight car.  It was in flames, and a number of men were pushing other cars from its vicinity to prevent them from catching on fire.  A man tapped him on the shoulder.  Turning, Ralph recognized one of the strikers.

“See here, Fairbanks,” he said, “I’m of the decent sort, as you know, but I think our position is right.”

“Does that look like it?” demanded the young fireman, pointing to the burning car.

“I’m not responsible for that,” said the man, “and I can’t prevent the hot-headed ones from violence.  I know you won’t join us, but I’m just friendly enough to give you a warning.  Don’t go on duty to-day.”

“I certainly shall, if I am needed,” replied Ralph.  “Your union is in bad hands, and can’t last.”

The man shrugged his shoulders and Ralph passed on his way.  A piece of coal came whizzing through the air a few minutes later from the vicinity of a crowd of loiterers.  It knocked off the young fireman’s cap.  He picked it up and walked slowly on.

When he came to the roundhouse, he found the doors shut.  Most of the windows in the place were broken in.  Several target rods near by lay on the ground, and at a glance Ralph saw that considerable damage had been wrought during the night.

“There must be a crisis soon,” he said, and went to the roundhouse door.  Before he was admitted several stones rained about him, thrown from behind a pile of ties.  Inside, Ralph found Griscom and several others among the older engineers and firemen.  All hands looked serious, the foreman particularly so.

“Glad you came,” said Forgan.  “There’s bad trouble brewing.  The strike has reached the danger point.  We can’t run any regulars from the depot and won’t try to to-day, but the Limited Mail must go to terminus.  Griscom is ready for the run; are you?  The regular engineer and fireman say they won’t risk their lives.”

“I did not see the train anywhere,” observed Ralph.

“There is to be no regular train, only one postal and one express car.  They will back down here in half-an-hour from the limits.  Here is a wire for you.  Came early this morning.”

With some surprise Ralph read a brief telegram.  It came from the headquarters of the Great Northern in the city, was signed by the president of the road, and read: 

“Come to my office immediately on reaching terminus.”

Ralph showed this to Griscom.  The situation was discussed by the men in the roundhouse, and the time passed by until a sharp whistle announced the arrival of the Limited Mail.

As Griscom and Ralph went outside to relieve those temporarily in charge of the locomotive, they were pelted from several points with pieces of dirt, iron and coal.  A crowd surged up to the engine.  Then a startling thing occurred that dispersed them more quickly than they had gathered.

As if by magic there appeared on the platforms of the two coaches fully a dozen guards armed with rifles.  The train now proceeded on its way without molestation.  At the limits the guards left it to protect other railroad property.

The only trouble experienced during the run was between Afton and Dover, when some missiles were thrown and two switches found spiked.  When they reached the city, Ralph tidied up and went to see the president of the road.

Mr. Grant received him with a pleasant smile, beckoned him to a comfortable seat, and, closing the door of his private office, said: 

“Fairbanks, we think a good deal of you, and I know you deserve that favorable opinion.  There are many trusted and reliable men in our service, but they do not think as quickly as you do.  You are familiar with people at Stanley Junction, and on that account I wish you to do an important service for us.”

“I shall be pleased to,” said Ralph.

“It is this:  Some one is working against us, some one is undermining us.  We now believe that the sympathetic strike, as it is called, is more the result of some plot than a genuine sentiment of unionism.  A man named Delmay, from the Midland Central, and a man named Evans, a discharged employe of our road, are at the head of the movement.  Both are persons of bad record in every way.”

“I know that,” murmured Ralph.

“We believe that these men are hired to promote the strike.”

“Why, by whom, Mr. Grant?” inquired Ralph in considerable surprise.

“That we wish you to find out.  All we suspect is that some outside party is inciting them to the strike to carry out some selfish personal ends.  You must find out who he is.  You must discover his motives.”

Ralph was perplexed.  He could not understand the situation at all.

“I will do all I can in the line you suggest, sir,” he said, “although I hardly know where to begin.”

“You will find a way to make your investigation,” declared the president of the Great Northern.  “I rely a great deal upon your ability already displayed in ferreting out mysteries, and on your good, solid, common sense in going to work cautiously and intelligently on a proposition.  You can tell Forgan you are relieved on special service and wire me personally when you make any discoveries.”

Ralph arose to leave the room.

“Wait a moment,” continued Mr. Grant, taking up an envelope.  “I wish you to hand this to Griscom.  The Limited Mail will not make any return trip to-night.  Instead, a special will be ready for you.  You need mention this to no one.  That envelope contains sealed orders and is not to be opened until you start on your trip.  The superintendent of the road will see you leave and will give you all further instructions needed.”

There was a certain air of mystery to this situation that perplexed Ralph.  He reported to Griscom, who took the letter with a curious smile.

“Must be something extra going on down the road,” he observed.  “Wonder what?  Start after dark, too.  Hello, I say ­the pay car.”

They had come to the depot to observe an engine, two cars attached, and the superintendent standing on the platform conversing with a man attired in the garb of a fireman.

The latter was a sturdy man of middle age, one of the best firemen on the road, as Ralph knew.  He nodded to Griscom and Ralph, while the superintendent said: 

“Fairbanks, this man will relieve you on the run.”

Ralph looked surprised.

“Why,” he said, “then I am not to go on this trip?”

“Oh, yes,” answered the official with a grim smile, ­“that is, if you are willing, but it must be as a passenger.”

Ralph glanced at the passenger coach.  Inside were half-a-dozen guards.

“Not in there,” replied the superintendent, “We want you to occupy the pay car here.  Everything is ready for you.”

“All right,” said Ralph.

“Come on, then.”

The superintendent unlocked the heavy rear door of the pay car, led the way to the tightly sealed front compartment, and there Ralph found a table, chair, cot, a pail of drinking water and some eatables.

“You can make yourself comfortable,” said the official.  “There will probably be no trouble, but if there is, operate this wire.”

The speaker pointed to a wire running parallel with the bell rope to both ends of the train.  On the table lay a rifle.  The only openings in the car were small grated windows at either end.

The official left the car, locking in Ralph.  The young fireman observed a small safe at one end of the car.

“Probably contains a good many thousands of dollars,” he reflected.  “Well, here is a newspaper, and I shall try to pass the time comfortably.”

By getting on a chair and peering through the front ventilator, Ralph could obtain a fair view of the locomotive.  The train started up, and made good time the first thirty miles.  Then Ralph knew from a halt and considerable switching that they were off the main rails.

“Why,” he said, peering through the grating, “they have switched onto the old cut-off between Dover and Afton.”

That had really occurred, as the young fireman learned later.  The officials of the road, it appeared, feared most an attack between those two points, and the sealed orders had directed Griscom to take the old, unused route, making a long circuit to the main line again.

Ralph remembered going over this route once ­rusted rails, sinking roadbed, watery wastes at places flooding the tracks.  He kept at the grating most of the time now, wondering if Griscom could pilot them through in safety.

Finally there was a whistle as if in response to a signal, then a sudden stop and then a terrible jar.  Ralph ran to the rear grating.

“Why,” he cried, “the guard car has been detached, there are Mr. Griscom and the engineer in the ditch, and the locomotive and pay car running away.”

He could look along the tracks and observe all this.  Engineer and fireman had apparently been knocked from the cab.  Some one was on the rear platform of the pay car, a man who was now clambering to its roof.  The guards ran out of the detached coach and fired after the stolen train, but were too late.

Rapidly the train sped along.  Ralph ran to the front grating.  The locomotive was in strange hands and the tender crowded with strange men.

“It’s a plain case,” said Ralph.  “These men have succeeded in stealing the pay car, and that little safe in the corner is what they are after.”

The train ran on through a desolate waste, then across a trestle built over a swampy stretch of land.  At its center there was a jog, a rattle, the tracks gave way, and almost with a crash, the train came to a halt.

It took some time to get righted again, and the train proceeded very slowly.  Ralph had done a good deal of thinking.  He knew that soon the robbers would reach some spot where they would attack the pay car.

“I must defeat their purpose,” he said to himself.  “I can’t let myself out, but ­the safe!  A good idea.”

Ralph settled upon a plan of action.  He was busily engaged during the next half hour.  When the train came to a final stop, there was an active scene about it.

Half-a-dozen men, securing tools from the locomotive, started to break in the door of the pay car.  In this they soon succeeded.

They went inside.  The safe was the object of all their plotting and planning, but the safe was gone, and Ralph Fairbanks was nowhere in the pay car.