Tunnels 02, Deeper

and, swooping around the back of the guard's car, belted down by the side of the train before Will could object.
    "There he goes again," Chester moaned, but just the same he and Will took off after the younger boy, keeping to the lee of the train like Cal was doing.
    They ran down the line of lower cars, passing the one in which they had spent the journey, then continued beside their higher-sided counterparts. Dust and debris sprayed over their heads, and they had to pause several times to wipe it from their eyes. It took the boys a full minute to travel the length of the train, enough time for the loading to be completed. A few remaining scatters of whatever the material was fell from the row of chutes, and the air was laced with a gritty dust.
    Uncoupled from the train, the steam engine was farther along the track, but Cal had tucked down beside the last of the higher cars. As soon as Will and Chester caught up with him, Will lashed out, cuffing his brother around the head.
    "Oi!" Cal yelped, raising his fists as if about to retaliate. "What was that for?"
    "That was for running off again, you stupid little spud," Will chided him in a low, furious voice. "If you keep doing things like that, we're going to get caught."
    "Well, they didn't catch us... and how else could we get through here?" his brother defended himself vehemently.
    Will didn't answer.
    Cal blinked slowly, as if to say his brother was being tedious, and simply turned his head away to look into the distance. "We need to go down th--"
    "No way," Will said. "Chester and I are going to check first before any of us does anything. You just stay put!"
    Cal obeyed reluctantly, flopping onto the ground with a bad-tempered groan.
    "You all right?" Will asked Chester as he heard a loud snuffling noise behind him. He twisted around to look.
    "This stuff gets everywhere," Chester complained, then proceeded to blow his nose by clamping each nostril in turn with his fingers to clear them of the dust.
    "That's disgusting," Will said under his breath as Chester pinched a dangling skein of snot and flicked it to the ground. "Do you have to do that?"
    Taking no heed of his friend's distaste, Chester squinted at Will's face, then examined his own hands and arms. "We're certainly well camouflaged," he observed. If their faces and clothes had been filthy before from the continuous stream of carbon-black smoke on the train, they were even filthier now after being showered during the loading of the freight cars.
    "Yeah, well, if you're quite finished," Will said, "let's recce the station."
    On their elbows, he and Chester edged around the front of the car until they had an uninterrupted view of the buildings. There was absolutely no sign of any activity.
    Making not the slightest effort to keep his head down, Cal disobeyed Will's orders and joined them. He couldn't seem to stay still, positively vibrating with impatience. "Listen, the railwaymen are in the station, but they're going to come out soon. We have to get out of this place before they do," he insisted.
    Will considered the station buildings again. "Well, OK, but we all stick together and only go as far as the engine. Got that, Cal?"
    They moved swiftly from the cover of the car, running half crouched until they came alongside the massive engine. Every so often it vented hissing jets of steam, as if it were a dragon in deep slumber. They could feel the warmth that still emanated from its giant boiler. Chester foolishly placed his hand on one of the massive plates of pitted steel that formed its slab-sided base and retracted it quickly. "Ow!" he said. "It's still really hot."
    "You don't say," Cal muttered sarcastically as they skirted around to the front of the massively proportioned machine.
    "It's awesome! Looks exactly like a tank," Chester said in schoolboy wonder. With its huge interlocking armor plates and giant cowcatcher, it certainly did resemble a military vehicle of some kind, an old battle tank.
    "Chester, we really don't have time to admire the choo-choo!" Will said.
    "I wasn't," he mumbled in response, still ogling the engine.
    They began to debate their next move.
    "We should go down there," Cal said forcefully, indicating the direction with his thumb.
    "Blah, blah, blah," Chester mocked under his breath, giving Cal a disdainful stare. "Here we go again."
    Will studied the area of the cavern his brother had pointed to. Across a stretch of about fifty yards of open ground was what could have been an