I’ve always like trains. I grew up in North Jersey, so I’ve always seen NJ Transit and the occasional freight train around. Now that I’ve been in the “Heartland of America” for just over a year now (I’d rather be near the kidneys or spleen personally) I see a lot more freight trains, and a few questions sprung to mind. Keep in mind that I’m and Electrical and not a Mechanical Engineer, so some of these might be pretty retarded:
1. What engine is in the locomotives? I assume its some sort of gas driven turbine, but what does the turbine turn? AC or DC generator? Driveshaft? What fuel does it usually burn?
2. Does the locomotive have some sort of “transmission” when it gets up to higher speeds?
3. Some single tracks seem to go for many, many, many miles. Is there some sort of “traffic control”? What if one track gets blocked? Do they re-route traffic? How?
4. Is there some sort of tracking system for the individual cars? I’m sure CP Rail, Soo Line, CX, BNSF and Conrail have their own cars. How do they keep track of 'em?
5. Do modern freight trains still have some sorta “caboose”? I haven’t seen one in recent memory, and it seems that they’ve gone the way of the dinosaur. . .
Just a few questions I wanted to ask. Is there a good book or hardcopy source of information I should look at?
Tripler
Black is hot, red is not, green is ground.
Most locomotives use diesel engines to drive DC motors, which actually power the train. There were a few attempts using jet engine power, but the noise and fuel consumption didn’t make it practical.
I haven’t seen a caboose since I was a little kid. Since they were usually the “home” of some of the brakemen, I don’t think they are really needed anymore with the newer technology on trains these days.
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*Originally posted by Tripler * 1. What engine is in the locomotives? I assume its some sort of gas driven turbine, but what does the turbine turn? AC or DC generator? Driveshaft? What fuel does it usually burn?
A. Most have diesel-burning piston engines turning generators that power electric motors.
2. Does the locomotive have some sort of “transmission” when it gets up to higher speeds?
A. No. No need for one with electric motors.
3. Some single tracks seem to go for many, many, many miles. Is there some sort of “traffic control”? What if one track gets blocked? Do they re-route traffic? How?
A. They have radios and dispatchers. I’m sure there are alternate routes.
4. Is there some sort of tracking system for the individual cars? I’m sure CP Rail, Soo Line, CX, BNSF and Conrail have their own cars. How do they keep track of 'em?
A. Magic. (IOW, I don’t know :))
5. Do modern freight trains still have some sorta “caboose”? I haven’t seen one in recent memory, and it seems that they’ve gone the way of the dinosaur. . .
Gunslinger is quite right. They are diesel-electric locomotives. The body of the locomotive houses a huge diesel motor which drives a generator. Electrical powers is transmitted to electric motors mounted on the bogies. They are esentially electric trains which carry their own little power station around with them.
Electric power provides the advantage of having massive torque at low speeds (or even a complete stop). An internal combustion engine conected directly to the wheels would be unfeasible as the clutch set-up would be huge and unwieldy, and very hard to use. This thread explains this nicely.
Even with electric power, these trains are incredibly heavy and difficult to get rolling. This is why freight trains are “loose-coupled”. Loose-coupling allows the locomotive to take the strain of each wagon one by one. That’s why freight trains make lots of creaking and banging sounds as they accelerate. Passenger trains, on the other hand, are lighter, and can be coupled more tightly to give greter passenger comfort.
Here in Australia (probably the same in the US), railways use the ‘block’ control system. It is interlocked with signals and points (switches, turnouts) to allow only one train in each block section at a time. In the old steam days, a “staff” system was used. The station master at a country station would hand the loco driver a special rod which he would carry with him to the next station. Trains could not proceed without possession of this rod. This prevented collisions. It also allowed the fireman to heat up the rod in the firebox before handing it to unpopular station masters.
The single lines are in more remote areas, so I guess sheer infequency of trains prevents delays and conflict. Closer to the cities, of course, it is all dual track. And yes, sadly, we got rid of our guards’ vans (US=caboose) ten or fifteen years ago.
The caboose presented a thorny problem for the railroads. The extra pulling weight, crew members and cost of rolling stock all contributed to it’s demise. Its replacement is known as the “ETD” (End of Train Device). It consists of a red lamp to allow spotting of the train’s last car.
There has been controversy over just how dispensible the caboose really is. Due to its construction (bay windows and/or roof cupola), crew members in the caboose were far more able to spot “hot boxes” (over heating axles) and other potential problems with railcars in the consist before they could threaten to derail the train. Many have questioned the wisdom of eliminating this important monitor of the train’s operability.
Cabooses today are used in limited situations such as transfer runs (transfering cars between yards of different RRs) or long ‘back-up’ moves [i.e. the caboose is in the front, the engine in the back, and the conductor radioes the engineer from the caboose to inform him what’s ahead - although nowdays this is more and more done with push-pull (engine on each end of the train)].
The FRED (or EOT device) will usually have monitoring equipment build in to measure brake-line air pressure (and other info), and will transmit this information to the engineer.
Also, most new locomotive production for North American Class I railroads is ‘Wide-Cab’ nowadays, providing room for the whole train crew and areas to perform the paperwork required (work formerly done in the caboose itself).
