The Chronicles of the Orbital Railroad

Model railroads in orbit must be extremely confident that the reliability of their own systems will not be in doubt." "Which raises the question," Torgut spoke up, "How are the _Sydney_ and _Prince Rupert_ going to track and control a train in orbit? If they don't have any pilots who can fly this sort of thing, they won't be able to control the train at all, and it will become a passenger liner instead of a railroad." "Not necessarily," Bury said. "It's not too difficult, if we can make a few changes to the design. We're not going to use the systems set up for the _Sydney_ and the _Prince Rupert._ " "This Union Station will be a railroad, but it's going to look more like a park than a railroad station." "I'm going to put in some tracks underground," Roadrunner told Bury. "That way, a train can go in and out of the station to pick up or drop off passengers just as easily as it can use them to get down to Dora's, and there's no need for it to stop anywhere else." "I don't see why we need to go to all that trouble," Bury said. "What are we going to do when a train enters the station and has to stop?" "I've found a way to make _that_ work," Roadrunner said. "So you're going to have the same train that is in orbit go to the spaceport and back?" Torgut said. "Yes, that's just the first step. Eventually, we'll be able to have the train go to Dora's and back, and even on to a spaceport on another planet." "That's a part of the plan I like very much," Bury said. "Showing that the Union Station can be used not only for sending mail but also for transporting people. It's a very interesting idea. I'll have to think about this carefully." "What are the pros and cons of all this?" Roadrunner asked. "The pros are that we can make a flying railroad, and we don't have to be able to control the trains by radio or by satellite. We can just let them go out on their own." "But they'll have to stop at Union Station before they go into space," Torgut pointed out. "What happens if they lose control and catch fire while they're in orbit?" Roadrunner thought for a moment. "Then they'll have to go down, and the space-station folks will have to go feed them." "That's rough." "I think," Bury said, "that the cons are bigger than the pros. However, I think that if we have working trains in orbit and can get them safely down to Dora's, we'll have a better chance of getting them to work on the ground." "And by that time, you will have improved the trains so that they can be controlled by radio," Roadrunner said. "That _is_ the advantage to the whole concept." "So what should we do now?" Torgut asked. "Do we have any more ground trains to load?" "Not this trip," Bury said. "We can get the two trains to the station, and then we'll have a few minutes of testing time before we go out to the spaceport." "Fine," Torgut said. "I'll start getting the trains ready so that they can be used to move freight and passengers into the station and back out again." "That's the way to do it. I'll take the fission engine and go get the two trains and bring them in." Torgut nodded. He was a very good tracker, and he had spotted the two trains early today. "I guess I'd better go and get the engineer of the _Prince Rupert_ ready to handle the engine as soon as the tracks are laid down." "I'll be there before you," Roadrunner said. "Wait a minute," Bury interrupted him. "Before you go, I want to have a talk with the engineer. We're going to put the fission engine in the big train, and it'll be the train that goes on the ground. We want to make sure that somehow the people who ride in it don't get hurt if the engine explodes." "I know," Torgut said. "I was just about to tell you. I've been thinking about it, and I've decided that we just shouldn't bother with any kind of protection system for the people riding in the engine." "Why not?" "Because the fission engine is twice as large as the train, and twice as heavy. When you put it together, there's not much between the front of the train and the back. We can't help it, even if we wanted to, but the two trains will just blend together, and the people riding in the front of the engine will be as safe as the people riding in the back." "I thought we were going to put the engine in the back of the train to make it look good," Roadrunner said. "No, no," Torgut said. "You'll be able to see the people riding in the engine from the back of the train, but it will be in the back just the same way that you can see them from the back of any of the other trains." "Still, I guess putting the engine in the back is better than taking any chances," Roadrunner said. "That's what I think," Torgut agreed. "I understand that the engine will be twice as big as the freight cars," Bury said. "If it's set to burn for thirty minutes, what will the train be carrying?" "About seventy-five tons," Torgut answered. "And what will it weigh?" "I think about a hundred and fifty tons," Torgut said. "And when the train is empty, it will weigh about two and a half times as much as the engine." "So what do we do if we lose control of the train?" "The only thing that can happen is that it goes into a dive and stops," Torgut said. "That's why we don't put an automatic control system on it, because we know that if the engine goes into a dive, it will stop. Even if there were such a control system, making the control signals direct to the engine would never work." "Then we don't put a control system on the train?" "Oh, no, certainly not," Torgut said. "If you put a control system on an unmanned train, it can cause a problem if its program goes wrong." "I see. I guess if it's programmed to show a red light and stop, it will stop." "No, it won't," Torgut said. "No one will stop the train because the light in the control box will be red. But all the people riding in the train will be in trouble, since they'll be sitting on top of a pile of dynamite." Bury nodded. "No one has figured out a way to make a train explode that doesn't go off by itself as soon as it leaves the station." "So why bother with the people riding in the engine if we don't have any way to protect them?" Torgut said. "They're going to be in more danger as a result of our choice than they would have been if we had stayed with the water-cooled fission engine and let it be controlled by a system that would have automatically stopped it if we lost control. I'd feel much better about the whole thing if we had used a system of protection." "I understand," Bury said. "We'll just have to find some other way to protect the people riding in the engine." "Okay, I'll get the engineer working on the engine and the rest of the train ready." "You might as well tell him that I want to have a talk with him. I'm going to sit at the back of the train and see how it all works." "I'll tell him," Torgut said. "Then we can both talk to the engineer at the same time." Bury went to the cab and sat down. There was a chair for him, and there was a window through which Bury could look out. The window was bigger than the window of a car, but not as big as the window of the front of a train. Bury looked out the window first and saw that the track was well laid out. The rails were smooth and level, and there was no evidence of any of the bumps that had been built into the track along the way. Bury took a notebook out of his pocket and started a notation of what he saw. It was a little after ten o'clock, and the sun was high in the sky. "Do you know what the time is?" Bury called to Torgut. "Yeah," Torgut said. "You're ahead of schedule, so I guess the best thing you can do is observe the procedures so you'll know what to tell the engineer." "I see," Bury said. "I think that the next thing I'll do is to make a correction on the schedule for the _Sydney_ and the _Prince Rupert._ " "Okay, I'll let the two of them know." The engine pulled up and stopped by the train just in front of the cab. Bury rolled the window down and leaned out over the edge of the cab. He saw that the locomotive's engineer was a big man with a prominent nose. He was carefully watching the train as it stopped, and he started to get out of the engine almost as soon as the train was still. "What's the matter, Einar?" he asked. "You running a little late?" "I'm afraid I'm running behind schedule," Bury said. "I'm not sure I can make up the time." "It's okay," the engineer said. "We are still ahead of schedule, but we have had some trouble with the train we're hauling." "What kind of trouble?" "The brakes on the train have failed, and we're not sure how the train got into that condition." Bury nodded. "I can see how that would happen." "That's just what we're going to find out," the engineer said. He held up a small bundle of tools. "I brought these along for a little trouble shooting." "I don't think I'll need any," Bury said. "I think we should go out to the train and look at it, and I'll tell you what to do." The engineer looked doubtful. "You don't know if it's going to be safe, sir." "Not until I see it," Bury said. "But I can get an idea of what the trouble is just by looking at the train." The engineer frowned. "I don't know. You might get hurt." "No, I won't get hurt," Bury said. "We've got a few broken windows, and I'll have to look inside a few of the cars. But I won't be doing anything very deep, and I won't go anywhere near a dynamite car. If I'm careful, I'll be fine." The engineer shrugged. "It's your funeral," he said. "I know," Bury said. "It's just that I want to get this train all ready to go by noon. If I'm not back by then, you can send the train to where it's going with a skeleton crew in the driving cab, and you can watch the rest of the train to see if anyone needs help." "But what if the train starts to roll?" "Well, you can stop it if you have to," Bury said. "I think you'll be able to stop it without much trouble." "I'll try to wait for you," the engineer said. "Good," Bury said. "I can't promise that I'll be back before noon, but I'll try. If I'm not, take the train to the spaceport and pull it up on the launch platform." "You won't be back in time to warn the crew of the launch platform about the danger?" the engineer said. "No, I guess not," Bury said. "I don't think the stuff about dynamite will be as dangerous as other things they run into in the spaceport. I think if they don't get blown up on the way into space, they'll be okay when they get back."