Numbers of locomotives required for mountain routes

[hiyo]

Does anyone know how different railroads decide how many locomotives to allocate to trains? Specifically, at what point does a railroad decided that 2 locos grinding up a steep grade at walking pace need a third loco or helpers to get over a mountain quicker/more efficiently?

I'm particularly interested in old Conrail operations and have found an excellent blog by a former employee.

We ground up another hill at full throttle and 8 mph. I could jog faster, but it was quite a show listening to the locomotives work up the grade. The EMD was blasting out it's high pitched turbo whine accompanied by the sharp, bass "whop, whop, whop" of the C36-7 trailing. The SD50 had EMD's new Super Series adhesion control and the GE had their response - Sentry Wheelslip Control. Both worked well as the locomotives maintained a good grip on the rail as the load meter moved steadily upward and edged into the red. We crested the grade had then braked down the other side. http://blerfblog.blogspot.com.au/2014/08/war-stories-episode-23-how-to-scare.html

Compare that with Horseshoe Curve operations where there are several locos on the front of train and a couple of helpers on the rear.

This is all information I'd like to incorporate into my own Trainz WIP mountain route. I can run heavy trains on 1.5 to 2.0 per cent grades but seem to need more locos than what the prototype would use. I'm not sure Trainz would be able to come close to replicating this test:

The test consist included the three SD60MACs, EMD's test car, and 110, 100 ton hoppers. Trailing tonnage was 14,700 tons. The destination was Enola where these 110 car trains were chopped down to 90 car trains in order to operated south through the B&P tunnel to power plants in Maryland. The train was right at the limit for tonnage on the west slope, so we had a pair of helpers tacked on the rear at Conemaugh for safety. Started to pull. Not moving. Dynamometer coupler in EMD's test car was showing less 100,000# per unit with quite a bit of variability. Lead unit is jumping up and down a bit. EMD advises the engineer to trust the wheel creep system and just keep pulling. Slowly, we start to move. After 12 minutes, we're only a few hundred feet down the track. Still not pulling anywhere close to 35% adhesion. http://blerfblog.blogspot.com.au/2014/08/war-stories-episode-26-emds-travelling.html

Cheers
Hiyo

 

[MeowRailroad]

I guess they decided to add helpers when one day, a westbound train going up a hill became an eastbound. :hehe:

 

[jkinzel]

http://www.alkrug.vcn.com/rrfacts/hp_te.htm


http://forums.auran.com/trainz/showthread.php?55876-Locomotive-HP-per-Ton

 

[norfolksouthern37]

Does anyone know how different railroads decide how many locomotives to allocate to trains? Specifically, at what point does a railroad decided that 2 locos grinding up a steep grade at walking pace need a third loco or helpers to get over a mountain quicker/more efficiently?

I'm particularly interested in old Conrail operations and have found an excellent blog by a former employee.



Compare that with Horseshoe Curve operations where there are several locos on the front of train and a couple of helpers on the rear.

This is all information I'd like to incorporate into my own Trainz WIP mountain route. I can run heavy trains on 1.5 to 2.0 per cent grades but seem to need more locos than what the prototype would use. I'm not sure Trainz would be able to come close to replicating this test:



Cheers
Hiyo

Sure Trainz can do this with properly configured locomotives and rolling stock.

 

[cascaderailroad]

Mostly it was trial and error, in the wayback days, and the PRR oftentimes had 2, or more, steam locos head end, and 2 more shoving on the rear ... and NS was oftentimes caught short of power, telling the train crew to see how far they get, and sent an underpowered 2 loco train up a 1.87% grade, stalling, or breaking couplers ... so they learned to add more 2 helper units, shoving on the rear.

 

[oknotsen]

Decision is based on cost / profit calculation.

Examples of questions being asked to make the decision:
Does the train or the resources involved make more money if arriving on the other end sooner?
Do we have resources available to add an extra engine?
How much money would the extra engine cost (both fuel and not being available for other tasks)?
Would this mean needing an extra crew?
Can we afford having the train stop to add a helper engine or is it cheaper to have the helper engine on the train the whole trip? Or is the gain less than the cost of adding the engine?

 

[289v8]

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[hiyo]

Thank you all for your replies, there's lots for me to read! If you haven't had a look already, that Conrail blog I was quoting is a really good read.

289v8 - where is that text from?

 

[hiyo]

Sure Trainz can do this with properly configured locomotives and rolling stock.

That idea had crossed my mind. I assume with all the work Jointed Rail puts into their (excellent) locos that their engine specs, weight etc is accurate, but is that the same for your rolling stock too?

The other day I ran 2x Jointed Rail C40-8Ws with 40x non-JR loaded coal hoppers and the locos seemed to struggle up grades. I'll have to try again with some of those new JR 100-ton gondolas.

 

[289v8]

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[cascaderailroad]

I once put a small switcher loco on a 1.87% grade and it pulled a 15,000 loaded train uphill :hehe:

There is an invisible loco asset "AI Brake" that adds braking power, and horsepower to a consist

 

[MeowRailroad]

I once put a small switcher loco on a 1.87% grade and it pulled a 15,000 loaded train uphill

Seems legit. I did this once where I was able to pull a big coal train with only 2 SW1500's on a flat area.

 

[norfolksouthern37]

That idea had crossed my mind. I assume with all the work Jointed Rail puts into their (excellent) locos that their engine specs, weight etc is accurate, but is that the same for your rolling stock too?

The other day I ran 2x Jointed Rail C40-8Ws with 40x non-JR loaded coal hoppers and the locos seemed to struggle up grades. I'll have to try again with some of those new JR 100-ton gondolas.

Yes they are. It all depends on what the grade is and what speed you need to move that certain weight of train to figure out how many locos you need.