Warden quickly completed these initial stages of his work. He was a past master at this sort of job, having trained himself to shift the gravel without making a sound before molding the plastic and setting the booby trap. He operated almost mechanically, and was pleased to find that the Siamese partisan, though new to the game, was nevertheless an able assistant. His instruction had been good—much to the delight of Professor Warden. There was still some time to go before daylight. He had brought with him a second contraption of the same type but slightly different, which he placed a few hundred yards further up the line in the opposite direction to the bridge. It would be criminal not to take full advantage of a night like this.
Warden had shown his usual foresight. After two attacks in the same sector the enemy usually got suspicious and proceeded to inspect the line systematically. But one never knew. Sometimes, on the contrary, he could not imagine the possibility of a third outrage, precisely because there had already been two. In any case, if the trap was well camouflaged, it might escape the most searching scrutiny—unless the search party reluctantly decided to rake through every bit of gravel in the ballast. Warden set his second "toy," which differed from the first in that it was fitted with a device to vary the effects of the explosion and cause another sort of alarm. The mechanism worked on a kind of delayed-action principle. The first train did not set it off, but simply started the mechanism working. The detonator and plastic them^ selves w
ere only affected by the weight of the following train. It was quite clear what the Force 316 technicians had in mind when they perfected this ingenious device which so delighted Warden's rational mentality. Quite often, when a line had been repaired after a whole series of accidents, the enemy sent the next important convoy through behind a screen of a couple of coaches loaded with stones and pulled by a useless old engine. Nothing untoward happened to the leading train. And so the enemy was convinced that his run of bad luck was over. Full of confidence, and without any further security measure, he launched the train that really mattered, and presto, the train that really mattered blew up!
"Never assume an operation is complete unless the enemy has been caused as much alarm and despondency as possible" was the leitmotif of the Plastic and Destructions Company, Ltd. "Always strive to multiply the number of unpleasant surprises and to invent fresh traps so as to sow confusion among the enemy just when he thinks he has at last been left in peace" was the firm's ceaseless exhortation. Warden had taken these doctrines to heart. After setting his second trap and leaving no trace of it, he again racked his brains and tried to think of yet another trick to play.
He had brought with him a few other "toys," just in case. He had several specimens of one of these, consisting of a round of ammunition fitted into a loose board which pivoted on its axis and snapped back onto a second, fixed, board pierced with a nail. These were antipersonnel devices. They were hidden under a thin layer of earth. They were the most simple sort of mechanism imaginable. The weight of one man was all that was needed to snap the round down onto the firing pin. The bullet went off and pierced the man's foot or, with any luck, hit him in the forehead, if he happened to be walking leaning forward. The instructors in the special school in Calcutta recommended scattering large numbers of these "toys" in the neighborhood of a "prepared" railway line. After the explosion, with the survivors (there were bound to be a few) rushing about in panic, the traps would go off and add to their confusion.
Warden would have liked to get rid of the whole lot as cunningly as possible, but his caution and reason prompted him to abandon this final delight. There was a risk of their being discovered, and the priority target was too important to warrant such a risk. A sentry coming across one of these traps would be enough to put the Japs on their guard against a possible sabotage attack.
Dawn was approaching. Warden wisely but reluctantly decided to go no further and started back for the observation post. He was fairly pleased to be leaving behind him a well-prepared area seasoned with spices designed to give an added zest to the main attack.
One of the partisans made a sudden movement. He had heard an unusual crackling in the forest of giant ferns which covered the hilltop. For a few seconds the four Siamese kept absolutely still. Warden had seized his Tommy gun and stood ready for any eventuality. Three low whistles were heard a little below them. One of the Siamese whistled back, then waved his arm and turned to Warden.
"Number One," he said.
Presently Shears and a couple of natives joined the group at the observation post.
"What's the latest?" he anxiously asked as soon as he caught sight of Warden.
"Everything under control. Nothing new. I've been here three days. It's all set for tomorrow. The train leaves Bangkok sometime during the night and should get here about ten in the morning. What about you?"
"Everything's ready," said Shears, lowering himself to the ground with a sigh of relief.
He had been horribly afraid that the Japanese plans might have been changed at the last moment. Warden, too, had been on tenterhooks since the evening before. He knew that the bridge was being prepared that night and had spent hours listening blindly for the slightest sound from the River Kwai, thinking of his two friends at work in the water just below him, constantly weighing their chances of success, visualizing each successive stage of the operation, and trying to think of any snag that might possibly crop up. He had heard nothing unusual. According to the program, Shears was to rejoin him at daybreak. It was now past ten o'clock.
"I'm glad you've turned up at last. I was getting a little worried."
"We were hard at it all night."
Warden looked at him more closely and saw that he was utterly exhausted. His clothes, which were still damp, steamed in the sun. His drawn features, the dark circles under his eyes, the growth of beard on his chin, made him look like nothing on earth. Warden handed him a flask of brandy and noticed how he fumbled as he seized it. His hands were covered with scratches and cuts, the dead-white skin wrinkled and hanging in strips. He could hardly move his fingers. Warden gave him a dry shirt and a pair of shorts which he had put out for him, then waited.
"You're quite sure nothing's planned for today?" Shears repeated.
"Absolutely. Another signal came in this morning."
Shears took a gulp, then gingerly started massaging his legs.
"Rather a tough job," he remarked with a shudder. "I think I'll remember that cold water for the rest of my life. But everything went off all right."
"What about the youngster?"
"The youngster was terrific. Didn't let up for a second. He was at it harder than I was, yet showed no sign of fatigue. He's now in position on the right bank. He insisted on settling in at once and staying put until the train arrives."
"Supposing they get wind of him?"
"He's well concealed. It's a risk, I know, but it's worth it. We've got to avoid a lot of movement round the bridge at this stage. And then the train might turn up earlier than we think. I'm sure they won't catch him napping today. He's young, and he's tough. He's lying up in a thicket which can only be reached from the river, and the bank there is steep. We can probably see the place from here. All he can see, through a gap in the branches, is the bridge. But he'll be able to hear the train approaching."
"Did you go there yourself?"
"I went with him. He was right. It's a perfect position."
Shears took out his field glasses and tried to spot the place in a landscape which was strange to him.
"It's hard to pin-point it," he said. "It all looks so different from here. But I think it's over there, about ten yards behind that large red tree with its branches trailing in the water."