Dumb Railroad Questions

[kerplode]

So I got this part time job recently to get me out of the house and make a little extra cash. The shop where I work is across the street from a major, and very busy, east-west BNSF rail. So I spend a chunk of each day standing at the counter and watching trains go by. Now I've always been fascinated by the workings of trains, but unfortunately, I only have a child-like understanding of the whole process. Anyway, I've noticed some things that I'd like to understand better. I know we have at least one train driver here, so I figure I might be able to get some better intel than just rando-googling.

So here goes...

- When assembling a train, how do "they" determine which locomotives travel "forward" and which travel "backwards". I assume this is some sort of wear-leveling measure for the drive gears and bearings...Is there like a forward hour counter and a reverse hour counter that someone tries to balance for each locomotive? And how do you turn one around? Drive out to a siding track somewhere and make a three-point turn or something?

- I notice that there are many configurations of locomotives...Lots at the front, a few at the front and some at the end, and sometimes even some at the front, some at the end, and a couple in the middle. How is this determined? By the total weight of the cars being moved? I suppose that's probably the case, but honestly, there doesn't seem to be much pattern to it to my untrained eye. I guess if you had a very heavy string of cars and put all the locomotives up front you might break a coupling before you got the thing moving, but sometimes I see short trains of just cargo containers that have pullers and pushers.

- Are the locomotives in the middle and at the end staffed, or are they slaved to the controls of the lead loco and run by some kind of remote control?

Finally...

- I've noticed that sometimes locomotives are just left sitting there idling...Sometimes for days at a time. Is their some reason that makes this advantageous, like maybe they're complicated to get started again, or they take a long time to "warm up" to be ready to pull? Now that I think about it, I've noticed this more in the winter, so maybe they're hard to get going when it's cold?

Like I said...Dumb questions... :-)

[ryr8828]

|The only question I can answer is that you don't turn them around, they go both directions. That's why they're facing the way they are.

[Diamondback]

Not a pro, but the general rule is you want at least the end locomotives in opposite directions to avoid turing at the other end of the line. In between doesn't really matter, they're really electrics with onboard generators basically and all the motors care about is voltage and polarity of it.

A cold diesel block is a BEAR to get cranked over again, it's usually cheapre to just leave 'em at a minimum-power idle than to install a layover heating system--1950s New York Central practice was to only install LOH systems on engines assigned to lines with either extreme (by Northeast standards) low temperatures or very limited facilities like overnighting away from a terminal.

[Coal Dragger]

So I got this part time job recently to get me out of the house and make a little extra cash. The shop where I work is across the street from a major, and very busy, east-west BNSF rail. So I spend a chunk of each day standing at the counter and watching trains go by. Now I've always been fascinated by the workings of trains, but unfortunately, I only have a child-like understanding of the whole process. Anyway, I've noticed some things that I'd like to understand better. I know we have at least one train driver here, so I figure I might be able to get some better intel than just rando-googling.

So here goes...

- When assembling a train, how do "they" determine which locomotives travel "forward" and which travel "backwards". I assume this is some sort of wear-leveling measure for the drive gears and bearings...Is there like a forward hour counter and a reverse hour counter that someone tries to balance for each locomotive? And how do you turn one around? Drive out to a siding track somewhere and make a three-point turn or something?

- I notice that there are many configurations of locomotives...Lots at the front, a few at the front and some at the end, and sometimes even some at the front, some at the end, and a couple in the middle. How is this determined? By the total weight of the cars being moved? I suppose that's probably the case, but honestly, there doesn't seem to be much pattern to it to my untrained eye. I guess if you had a very heavy string of cars and put all the locomotives up front you might break a coupling before you got the thing moving, but sometimes I see short trains of just cargo containers that have pullers and pushers.

- Are the locomotives in the middle and at the end staffed, or are they slaved to the controls of the lead loco and run by some kind of remote control?

Finally...

- I've noticed that sometimes locomotives are just left sitting there idling...Sometimes for days at a time. Is their some reason that makes this advantageous, like maybe they're complicated to get started again, or they take a long time to "warm up" to be ready to pull? Now that I think about it, I've noticed this more in the winter, so maybe they're hard to get going when it's cold?

Like I said...Dumb questions... :-)

OK, I will try to explain this:

1.) Locomotive consists are assembled by the yard crews, hostlers, or roundhouse staff for a train based on horsepower per ton requirements of that train. The direction of travel is meaningless to the locomotive from a performance or wear standpoint, so as long as one unit in the consist is short hood forward on the point it’s good to go.

The locomotives keep very detailed operating logs on direction of travel, throttle settings, tractive effort, and a whole bunch of other diagnostic information. This helps with maintenance but as the engineer I could care less.

Locomotives can be turned around on a turntable in a roundhouse, if equipped, or by y’ing at a track junction with two possible direction of travel onto the line being joined. It looks like a “Y” where either spur to the left or right joins the new line. Just throw some switches and get pointed the way you need to be facing. I’ve done this with entire trains.

2.) Locomotives numbers and positions are determined by the tonnage, length, and makeup of the train accounting for the maximum grades on the route. Sometimes operating conditions like very cold weather are also factored in if the yard rats and powers that be are paying attention… which is rare.

Locomotives distributed at the end of or in the train are distributed power. They are not manned, but are controlled from the lead locomotive, I can set them to mirror what the lead is doing or run them independently. Usually BNSF places locomotives at the front and rear of a train, but will sometimes place a DP consist in the center or rear 1/3. Depends on the factors above. The goal is to be able to move heavier trains than a conventional consist. Coupler knuckles are good for roughly 390,000lbs of raw draft force being applied. If all the force is draft force from the head end and a consist has enough power (3 locomotives can easily exceed that number), you can rip the train in two. Distributed power helps with this issue.

Air brake performance is drastically improved on a train with distributed power, not only in application but recovery of brake reservoir and brake line air pressures so brakes release. The distance between air compressors/main reservoirs are much shorter and there is less volume for each compressor to try to maintain. In very cold weather this is the difference between being able to operate a heavy long train, or have the brakes apply and never release. I have had many trips where I lost my air due to cold weather and had the brakes set and not release.

One exception on staffing locomotives is the use of helper locomotive sets. These are manned, usually single, double, or triple locomotive consists that are stationed at the bottom of unusually steep long grades. Rather than devote a huge amount of power to every train, we use helpers to shove trains up the hill. This is a great job for the guys with enough seniority to hold them.

3.) Most of our fleet of locomotives have an auto start/stop feature now. So when they are parked they can decide for themselves when to idle or shut down for fuel conservation. The engine has to run to power the air compressor to maintain main reservoir pressure for the locomotive air brakes and train air brakes, so they’ll kick on to do that.

In very cold weather they might run continuously because the coolant is strait water with a corrosion inhibitor, and if the engine block gets too cold the computer will dump all the water if a restart isn’t possible. Then you have a 205 ton brick until 300 gallons of cooling water can be pumped in. The programming of auto start/stop decides at a certain temp that shutdown is not an option.

Older locomotives will just be isolated, locked up, and left idling in cold weather.

[Diamondback]

Thanks, CD; I was hoping you'd chime in with the "now" to add to my long-outdated "back then." :)

[sva01]

Coal Dragger, this thread gets me wondering what the cost of a locomotive is. You have any info on that?

[Diamondback]

Around $2 mil. https://worldwiderails.com/how-much-do-locomotives-cost/

Bear in mind, RR's seldom buy locomotives outright, they sign long-term leases with finance companies who pay for the locomotives to be built to the customer RR's spec. Typically IIRC 15-30 years, with an option to buy at end of lease or return for the lease company to resell, re-lease to a new operator or trade-in as parts to strip for remanufacturing into new locomotives.

[kerplode]

--Knowledge dump--


Dude, this is awesome...Thank you for taking the time to educate me!

[Pacific5th]

Thankfully Coaldragger got here first so I didn’t have to write all that. I will add that locomotives do not have a transmission. The motor makes power for the traction motors on the wheels themselves. It’s essentially a large generator on wheels and because there is no transmission they work equally well forward or backwards although except in extreme situations the leader is always “shorthood” or cab forward.

Also consists are built for the weight of a train and routing. Example a 16,000Ton grain train on a flat route only needs about 1.0 Horse power per ton to move the train so about 4 locomotives. But that same train going over a mountain may need up to 8 engines placed in the front, middle and rear of the train.

Trains that are a high priority and need to get up and go faster will get enough power for 3.0-4.0 horse power per ton.

[SteyrAUG]

Awesome thread. Interesting questions, Sheldon quality answers.

https://www.pinkvilla.com/files/styles/large/public/sheldon_cooper_trains.jpg?itok=EvVhsuBe