Locomotives

[jedirailfan98]

For ultimate realism in my simulations, does anybody know how railroads delegate power? Is there any system, based on type of load (i.e. Manifest, or intermodal), Priority, or location, of distributing locomotives to each train?
Or if there is no set system, as is my suspicion, what trends have you observed, over your long experiences train watching?

[BoostedFridge]

For ultimate realism in my simulations, does anybody know how railroads delegate power? Is there any system, based on type of load (i.e. Manifest, or intermodal), Priority, or location, of distributing locomotives to each train?
Or if there is no set system, as is my suspicion, what trends have you observed, over your long experiences train watching?

This is a really open ended question, that has varying answers for each railroad.

For the most part, the railroads will try to use the least amount of power to get the train over the line. Each type of train will have a horsepower per ton rating for each section of railroad. On most railroads, high priority intermodals will have a higher HP/T rating to allow them to maintain as close to track speed as possible for as much of the route.

Distributed power comes down to grades on the lines the train will travel over, length of train, and weight.

To properly recreate prototypical power distribution for use in Railworks, I would suggest studying pictures and videos of trains in the area and time period that you are modeling. There is an infinite number of Youtube videos to assist in this. Also, searching a site such as RRpicturearchives.net, by location works well also.

[GERUNIMO625]

Hello,

If your really curious, we can get into it...
We will need some basic information.
(I will be using information from an actual train, UP's ZLAG1. I'm too lazy to figure out the math on my own, and I had the paperwork readily available, floating around the trunk of my car.)

Anyway, we'll need (depending on the company) information that might be available either from a Timetable, or some sort of "Superintendent Bulletin" or "System Special Instructions".
Also, you will need to be either good at math, or have a calculator.

We will first look for our train tonnage. In this case its 6448 tons.
We will also need the Tons per equivalent Powered Axle (TPA) limit for the territory to be traversed, here it's 172.
Now we take 6448 / 172 = 37.488 (Always round up) SO, final answer, 37.5 Is our Equivalent Powered Axles or EPA.

To find EPA of a locomotive your going to have to scour the internet. I'm not sure where to find that information outside of a work environment... Sorry!
BUT! I can give you what I have on my paperwork:
(We have 4 locomotives, 2 on the headend and 2 DPU's) They are as follows:
UP 6446 a C44AC locomotive has an EPA of 12.1
NS 9739 a D9-44CW locomotive has an EPA of 11.5
-----DPU's-------
UP 6546 a C44AC locomotive has an EPA of 12.1
UP 4313 a SD70M locomotive has an EPA of 10.4

So now add those 4 numbers together:
12.1 + 11.5 + 12.1 + 10.4 = 46.1
So, to pull our train we require an EPA of 37.5 and we have 46.1 at our disposal.
If we had more engines then the 4 we do, we would either isolate them, but more then likely shut them down to save fuel.

There is actually much, MUCH more we would need to know in the REAL world, such as Equivalent Dynaminc Brake Axles (EDBA), Tons Per Operative Brake (TPOB), placement of the power within our train in regards to blocks of cars, types of cars, loads of cars, etc., etc., etc.

OH! I almost forgot!
If you want to verify your actual TPA verses the limit of 172 use this equation:

Train Tonnage / Total EPA = Actual TPA
So, our actual TPA is 139.869 (again, round up) TPA= 140 )So again, we are under the limit.)

I left out ALOT in an effort to keep it simple but that should get you started.
Good Luck!


P.S. If you mean't which kind of engines get used on certain kinds of trains then I can tell you that too. Most of the time, its first come first serve. But reliability, gearing, DPU capability, are they due for inspections, or type of locomotive can all be factors. As an example, UP often puts SD70M's as leaders on Z-trains (without DPU's) because they are reliable. Another example, some locals use 4-Axle engines because certain industry leads turn too tightly for 6-axle engines to navigate without derailing. Also of note, all UP trains that operate in my neck of the woods (ex. CNW territory) must have UP engines as a leader, because foreign power doesn't have the CNW's Automatic Train Control (ATC) cab signal system; if you ever see a rerouted Amtrak train on ex. CNW tracks it will have a UP motor on the head.

[jedirailfan98]

Thanks Guys!

[GERUNIMO625]

Also, I forgot to mention that (atleast on the UP) our stack trains usually have power ear marked for them.
Or, simply they hold the inbound power from one train for the outbound train, i.e. IG4TA will get the ITAG4's power.