"Okay, it's moving back," Helling said. "I guess this thing--"
Suddenly, as abruptly as it had begun, the gantry halted, its steel
wheels screeching to a stop along the tracks.
"What happened?" Ramirez's eyes narrowed as he gazed out through the
viewing window. A red indicator had come up on the console, flashing.
The gantry, bathed in floodlights, was just standing there, stubbornly
still.
"The control went into a safety mode." The German was staring at the
console. "According to the lights here, the track sensors shut it down.
Maybe the rails are obstructed."