Single Locomotives on Class 1 Railroads

[west willow and laurel]

Hi All:

 

Does anyone know the length of a train that a class i railroad might only use a single locomotive for? Any pictures?

[ricktrains4824]

Sure, my avatar for one. 

Yes, I know, that's not a class 1, nor the point of your question. I just couldn't resist the joke. 

Now, as far as the real answer....

I have seen (and have a picture of it somewhere in my other computer....) a class 1 (NS) run a mixed manifest on their former NKP main line through Erie Pa. with just one SD40-2, and about 25 cars, and even a caboose on the rear of yet another one-loco NS train, but it was MOW rail-replacement train, with a GEVO leader. I've also seen Amtrak run single units on some of their passenger trains, one I got a picture of in Altoona, a 8-40BHW leader with 7 passenger cars, this past spring! 

Edit: really stinks that it didn't turn out very good. I would have absolutely loved that shot....

I'm sure they run others as well, and these are just 3 that I have seen recently. (All 3 in the last 2 years.) I have seen others before this as well. So they do run them.

[ndbprr]

It isn't length necessarily as much as it is tonnage. Most times that will be the limiting factor.

[NeO6874]

tonnage, grades, etc. all affect the required tractive effort, dynamic braking, etc. (that is, the number of locomotives).  

Really nasty areas (see: Horseshoe Curve, Cajon Pass, etc) may also require helpers for additional down-grade braking (and not so much the "uphill push").

[mlehman]

This is the Norfolk Southern, which comes past my house a couple of blocks away. I actually own part of the old Wabash line that was reconfigured several times, before using the old P&EI/Conrail line in from the west as it does now. The NS serves two industries on this side of town, an asphalt/road coating plant and a plastics plant, plus others from time to time, mostly using the P&EI's old Urbana yard.

Here's the motive power, which typically is a GP38-2. Sometimes they show up with a pair of six-axle units, but this is likely when they have lots of business with the grain elevator on the west side of town. Sure not needed over here. And it's pretty darn flat around here, too, so a little HP goes a long way.

Here's part of the train it brought, which consisted of plastic pellets and maybe a few grain cars stored out of the way for a customer on the west side.

Typically, the train consists of 6 to 12 cars. No shoving platform, as there are runarounds available if needed, so a FRED is used on the rear.

 

[cx500]

Probably anything a single unit can haul on your own model railroad will be prototypical.  It is a function of total tonnage and maximum grades, and that applies both in real life and in model form.  I've seen 80-100 car trains pulled by a single modern locomotive on both CPR and CNR.  The downside to a single unit operation is that if the locomotive fails the train is completely dead where it comes to a stop, blocking the line until rescue is arranged.  For that reason some roads prefer to have at least two on a train, and of course mostly it is required by the tonnage.

If you are modeling an earlier era with 1st generation power the maximum length of train is generally shorter of course.

John

[cv_acr]

I've seen a CN train go by with 3 engines and a single car (they dropped off the rest of their cars at another yard before it passed me) and the very next train was a one-unit wonder with 40-50 cars, straining to pull up the grade at that location.

[chatanuga]

85 cars in the first train of this video I shot in 1996.

https://www.youtube.com/watch?v=5wNBiiqPu9s

Kevin

[tomikawaTT]

Another, "How long is a string?" question.

On the flatlands, a single unit can drag away every car on the longest track in the empties yard.  Where the scenery stands on edge, the same unit might be hard pressed to pull three full 100 ton capacity cars up a sustained 2.5% grade.

Then, too, what is the unit?  Is it an SD70MAC, or a rejuvenated GE 44 tonner?  The big six-axle monster can start a LOT of tonnage.  the 44 tonner MIGHT be able to move the six axle, but only on level track.

Our prototypes have books full of tonnage tables (now usually found as data bases in computer memory) and employ various mathematical fudge factors when the weather is less than ideal to figure out the optimum combination of tonnage and horsepower to get trains over the road.  In a way, it's too bad that we don't have something similar.

Chuck (Modeling Central Japan in September, 1964 - 2.5% grades, short trains, single units)

[tcwright973]

Last Saturday I caught this locomotive pulling a string of gondolas eastbound on The Fort Wayne line between Conway Yard & Pittsburgh, I'm guessing about 30 cars. This might have been an empty slab train returning, but I really don't know.

[west willow and laurel]

Thanks everybody. Very helpful, as usual.

 

Ian

[west willow and laurel]

That looks very good. Thanks.

 

Ian

[andrechapelon]

I assume you're referring to diesels. It was general practice in the steam era to use a single locomotive on a train unless it needed a helper.

There's a picture in a a very old edition of "Pacific News" of an SP F7 A unit with at least 50 cars in the San Joaquin Valley. Sorry, can't remember the date other than it was in the 60's. Picture was taken by Henry Luna, one of the founders of the Pacific Locomotive Association.

Andre

[riogrande5761]

The D&RGW ran a high priority intermodal train in the 80's called the Railblazer.  While it typically ran with 2 or 3 GP40's, occasionally there was not enough trailer traffic and the train was short enough to allow a single GP40 to pull the train across the entire system from Denver to Salt Lake City, or visa versa.  There are photo's of such trains in some of my books.

[wabash2800]

Sometimes I've seen NS use one unit on a Roadrailer out here in Indiana as the trailers are relatively light compared to regular freight cars. I'm thinking max allowed is about 133 trailers, though that's changed over the years. And I'm sure that train had the max. Incidentally, if you didn't know, NS is phasing out the Roadrailers and is slowly replacing cars in the trains with flatcars with trailers on them. It's getting harder and hard to find a pure train of Tripple Crown Roadrailers. Also, you might see more trains in general with just one unit if NS can get away with it, as like CSX, NS is despartely short of locomotives (and crews). Business is really booming.

Victor A. Baird

www.erstwhilepublications.com

[west willow and laurel]

Very informative replies, as usual. Thanks all.

 

Ian

[jeffhergert]

In the name of fuel conservation, you could be seeing a lot of one engine trains and not even realize it.  I've had a few trains where I was allowed the use of one engine, even though there were more in the consist. 

A few weeks ago I had 70 cars, about evenly split between loads and empties, with 5 engines in the consist.  Since the total tonnage was within the capability of the lead engine on my territory, it was the only one allowed to be used.  The rest were to be shut down to save fuel.  In effect, a one engine train.

Jeff

[joe323]

jeffhergert

In the name of fuel conservation, you could be seeing a lot of one engine trains and not even realize it.  I've had a few trains where I was allowed the use of one engine, even though there were more in the consist. 

A few weeks ago I had 70 cars, about evenly split between loads and empties, with 5 engines in the consist.  Since the total tonnage was within the capability of the lead engine on my territory, it was the only one allowed to be used.  The rest were to be shut down to save fuel.  In effect, a one engine train.

Jeff

 

 

So in effect the other units were cars albeit very heavy cars that would reduce the efficiency of the running unit.  I am no expert but this seems kind of odd have one or two locos dragged around as dead weight.  Also do loco have a Neutral position like an automobile and how is it set?

[NeO6874]

No, they don't have a neutral like in a car add there is no mechanical link between the wheels and the engine.

Though, shutting them down would have the engine shut off, and the reverser set in neutral ( I.e. The circuit between the generator and traction motors is open)

[Kyle]

Any time you lug around more weight, your fuel economy and proformence drops.  In cars, the ones with more options like entertainment systems and 4 wheeldrive don't get as good as fuel economy as the stripped base models. However if those units ran by themselves, all of them would use more fuel, like towing 2 other pickup trucks, or driving all three.  The one vehicle towing is more fuel efficant.  

 

[Redore]

I very rarely see BNSF or CN trains with one engine outside of switching districts.  I think it has to do with reliability of the locomotives.

[big daydreamer]

Sometimes CP has short trains pulled by a single GE ES44 or AC4400CW.  I have seen this in Toronto.

[PM Railfan]

The long since gone RF&P used to run a local northward out of fREDNECKSburg Va around 7pm. I used to railfan at Dalghren Junction where the local would do some simple switching then proceed north. Slight grade at this spot. One adventure particularly stands out that answers your question also.  It wasnt a piece of cake but the single GP40 (the local was always a single unit) walked out of the junction head held high with 40 cars! I was shocked. I dont remember taking pictures but I use to record (cassette) in those days. I know I taped that and wish I still had that recording!   

[DavidH66]

I've seen a CSX Coal empty with about 50 cars be powered by a single AC4000W, and on the flip side I've seen a 12 car NS Local be powered by three SD40-2's

[Atlanta Dave]

As NDPRR wrote the issue is usually not length but tonnage.  THere are many other factors involved however.  What type of work will the train have to do?  Does the Class I road have a shortage of power?  Does the area being switched require only 4 axle units?  In this day and age I seldom see single locomotives on long hauls.  However, for industry work or short runs I see single units frequently.

[Lake]

DavidH66

I've seen a CSX Coal empty with about 50 cars be powered by a single AC4000W, and on the flip side I've seen a 12 car NS Local be powered by three SD40-2's

 

David, you may have seen three SD-42's, but only the lead unit would have been running.

Now maybe they came back from where 100 cars were droped off and needed the 3 engines running.

Or maybe on the way to pickup more loaded cars that need the power to get over a grade. Railroads do not run any more power on a train then needed, no matter what one my see.

Maybe 2 engines needed to be moved to a location where needed and they were tacked on to the train. They would not be under power.