"Where do you think it goes?" asked Fred while removing two steaks from the oven.
"The tracks look like they are in good shape and they are shiny where the wheels ride on the tracks, so trains are currently using the tunnel. If someone started walking along the tracks and a train did come, there is no room to hide." continued Martin.
"There usually is a tunnel between the two sets of tracks. The size is about right for two train tunnels and a middle tunnel for workers and cables."
"Could be. But how far would it be to the next door?"
"No way to tell. I guess that some brave person will need to chance it." said Fred.
"Or some machine." stated Martin, while slicing off a piece of his steak.
The next day Martin had a small door cut into the train tunnel and lowered a man down to measure the voltage on the third rail. He then began construction of a suitable remote controlled robot and repeater system. This design was simple enough that it took only a week to finish it. The short time was because he had a similar unit that he had built and put onto the shelf. The robot would use the standard repeater units that he currently used in order to communicate with the digging machines. These would be powered directly from the third rail of the train track with a slightly modified power circuit.
When the new robot was completed, Martin lowered it down into the train tunnel through the small door. He then closed the door and stuck an antenna through the hole that was originally drilled for the camera.
It was a bit of a walk back to the control rooms, but because of his excitement this only took fifteen minutes. He powered up the reserved control station and sat down in his comfortable control chair.
Martin drove the robotic car down the tunnel for a quarter mile without seeing any doors. By now the control signal strength was getting low so he drove over to the third rail and connected clips to it. This robot was battery powered and the power from the third rail was used to top off the charge. He placed one of the repeater units so that it would not be seen by passing trains and connected it's power leads to the third rail.
As Martin was driving away from the third repeater he heard a rumbling noise.
The robot had been painted the same color as the concrete floor and all shiny spots had been covered accept for the camera lenses. Martin backed the robot to the tunnel wall, shut down the lights and turned towards the direction that the train was travelling so that the camera lenses would not be seen. The train passed the robot and Martin rotated the robot get a better view.
The train looked exactly the same as a BART train (Bay Area Rapid Transit. This type of train runs regularly within the San Francisco bay area), Even the paint scheme was identical. This made sense to Martin and gave him a clue as to the owner of the tunnel. If the tunnel was owned by some government agency, the trains could be diverted from the existing transit system.
Martin drove for three miles down the tunnel. He then decided that he had gone far enough so that he had passed what should be the minimum distance between the supposed doors, and besides, he had no more repeater units. He turned the robot around and drove for the new door, leaving the repeater units in place for the next run.
The robot traveled easily on the smooth concrete within the narrow space between the concrete rail ties and the tunnel wall. Within ten minutes the robotic car was passing the small door that had been cut.
Martin had driven about an eighth of a mile past the door when he saw an entrance door on the other side of the tunnel. His wheeled robot had no way to cross the tracks to see weather it was locked, but now he knew it was there. After parking the robot near the door that had been cut, and connecting it's charger to the third rail, Martin turned off his control station.
It was a short walk to the office of the manager of new construction.
"Hi Jerry" greeted Martin.
"Hello Mr. Davies". replied the manager of new construction.
"I have a job for one of your operators. Should only be for a day or so."
"Ok." Jerry stood up and led Martin back to the control consoles and tapped one of the operators on the shoulder.
"Yes Mr. Singleton ?" said the operator after flipping off the main beam of his digging machine and turning to look at Jerry and Martin.
"Hi Jeff. Mr. Davies has a short job for you. You will work for him for the next day or two." ordered Jerry.
"Ok." replied Jeff. Jeff was a young looking black man in his twenties, dressed casually in a pull-over shirt and jeans. He had been both working and living in the tunnels for around five years and had become one of Jerry's most proficient operators.
"Just park your machine and meet me here in an hour Ok?" asked Martin.
"Alright Mr. Davies." agreed Jeff.
Martin and Jerry walked back toward Jerry's desk and chatted along the way. Martin took a nearby elevator up to the top level, just below street level. He walked a short distance and climbed up a ladder before uncovering a peep hole in a trap door. Satisfied that no one was nearby, He opened the trap door and climbed up into an alley, just behind a dumpster. After a short walk down the alley, Martin went down the street and entered a bar, then ordered a rum and coke while taking a bar stool next to a bearded man in a dark brown coat.
"Nice day" said the bearded man, his speech slightly slurred.
"Yea, only a few clouds." replied Martin.
"You look a bit pale, you feeling Ok ?" asked the bearded man before taking a sip from his Budweiser.
"I'm Ok. It's just that I spend most of my time indoors. Work is busy right now." explained Martin, handing the bar tender a ten.
"That's a shame with the weather the way it is. I drive a back hoe, when I can get work."
"Maybe your right. It's been a while since I had a vacation." said Martin, sipping his drink and wondering if the old drunk actually had a back hoe.
When he had finished his drink, Martin bid farewell to the bearded man with a nod of his head, then left the bar and went back into alley. He opened the specially constructed aluminum manhole cover and climbed down the short ladder. He then walked back to his reserved console where Jeff was waiting patiently.
"Hi Jeff." said Martin while flipping on his console. "I have built this small robot with wheels on it. The thing drives just like a remote controlled sports car. Notice the pile of repeaters ?" asked Martin, gesturing towards an auxiliary monitor above the console.
"Yes. The plugs look different." observed Jeff.
"Correct. These clips will connect to the third rail. It doesn't matter what plug goes on what rail, but they need to be connected like this". Martin demonstrated with his remotely controlled manipulators by attaching one of the clips to the rail. Jeff was watching on the auxiliary monitor as Martin was looking through the monitor shroud at the stereo image. "So that when a train comes by, the leads won't be cut." As Martin was talking he was also using the arms on the robot to connect the other clip from the repeater to the rail.
"Ok, I understand" said Jeff.
"If you place them like this so that the antenna is pointed towards the wall, we will get the maximum range while still not being too visible to the passing trains."
"Looks easy enough."
"Ok. These repeaters with the microphone units on them need to be placed last. The idea is to be able to hear a train as far down the track as possible. Ok, give it a shot." ordered Martin while getting out of the control chair.
Jeff sat in the control chair and began loading some repeaters into the carry pouches of the robot. He continued until all of the pouches were full. He then turned the robot in the direction of the door that Martin had discovered. Receiving a nod from Martin, Jeff drove the robot down the tunnel.
"Ok, now watch your control signal strength. If you go too far without placing a repeater we will need to send a rescue robot. Also watch your battery power. When it gets to about a quarter you will need to connect the charger to the third rail. Also, when you park, be sure to point the lenses in the direction of the travel of the train, so that the driver won't see any reflections." cautioned Martin.
"Alright." Jeff had already figured these things out, but dutifully listened anyway. He continued to drive the robot down the tunnel at a reasonable ten to twenty miles per hour.
"Ok, the signal strength is getting pretty low. Lets place a repeater." instructed Martin, pointing to the image of a signal strength meter on yet another console monitor. Jeff was unable to see Martin pointing at the monitor, because his eyes and part of his face were covered by the shroud. The meter was duplicated near the bottom of the stereo image that Jeff was looking at.
"Ok" agreed Jeff.
Jeff slowed the robot and drove over to the third rail. When the robot was stopped, he flipped a toggle switch on top of the right joy stick, putting the robot in park mode. He reached up and put his hands into the manipulator gloves, then pressed a button with his foot. The manipulator gloves gently pressed his hands into positions that were closer to the positions of the arms on the robot, when the positions matched, a green light came on. Jeff pressed another button with his foot and now had control of the remote arms of the robot. He withdrew a repeater unit from a pouch and placed it as Martin had demonstrated. Flipping switches, he placed the robot into run mode and drove on down the tunnel while glancing at the control signal strength, now at it's maximum reading.
"Perfect. Here is my card with my home number on it. Call me when all of the repeaters are placed. Don't rush, and be sure to listen for any trains." coached Martin before walking towards the elevator.
Martin spent the rest of the day watching TV and dealing with the stock market on his computer. The next afternoon Jeff called.
"Hello Mr. Davies"
"Yes ?" answered Martin, after picking up the phone.
"This is Jeff. I am at the airport"
"How come?, do you need a lift ?" asked Martin.
"No. The robot is under the airport. The tunnel goes under San Jose airport. There is a turn-around for trains and another tunnel to Moffet field." explained Jeff.
"Oh, very good. I will be right down." said Martin, before replacing the phone and walking to the trap door in his hallway. He took over the controls for the robot and drove around the train station. The station was just as Jeff had said, with one sign saying Moffet Field, and another that said Santa Cruz, for the other direction.
"Ok. Jeff, I have this beeper," explained Martin, referring to a pager sized device attached to his belt. "I want you to listen for any trains and press that red button if you hear one. Do you need to take a break or anything ? because I don't want you to leave this chair until I get back. I may be in the path of the train when you press the button, and this could give me enough time to make it out of the tunnel before the train."
"Ok, give me fifteen minutes." requested Jeff.
"Ok. I'll meet you back here." agreed Martin.
Martin went to his shop and picked up a tool kit that he had prepared a couple of days ago. When he had met Jeff, he called Jerry and then walked to the door that had been cut into the tunnel. Jerry lowered a ladder into the tunnel and Martin climbed down. Stepping over the third rail, he walked down the tunnel and over to the door that had been discovered by his robot. The metal door opened easily and he put one foot on a metal rung and stepped into the middle tunnel. There was barely room to walk in the middle of many cables and pipes. The pipes were securely mounted, being bolted to the concrete walls and ceiling.
Martin selected one of the thick cables and cut into the rugged insulation that was covering it. Inside of this one was braided copper. Thankful that his knife was insulated, because this was a high current power line, he selected another cable. This one contained fiber optic strands and also a bundle of regular telephone wire. Martin attached a number of wire taps to as many of these as there were channels on his repeater device. When he was done, he covered his work as best he could and connected the antenna of the repeater to the metal door, before closing it and leaving the tunnel.
Most of the conversations were meaningless, but Martin listened during most of his free time anyway. His computer monitored all of the taps at once and allowed Martin to switch between the active channels and search for key words. The setup worked well, but no one talked about anything interesting. Most of the conversations were between husband and wife. Some people said that they were in remote bases anywhere from the north pole to bases in various deserts. No one said they were in Santa Cruz. This must be some secret base if such care was taken about security, mused Martin to him self.