I was looking at information on a steam locomotive and read that at the end of its run it had been assigned to helper service in the mountains.
Do the railroads that use helpers typically use units that are nearing their end or can you find more state of the art locomotives? Put another way how do the railroads decide what to use for helpers?
Rick
They can use both. They might use older engines or they might buy brand new engines specificaly for that service. Or they might use the same engines they use for normal service and just assign them to helpers for a while.
Often they assign less reliable engines as helpers. Helpers tend to be closer to a home base, only make "short" runs and have considerable down time between runs, as opposed to a regular service engine that might be pulling almost continuously for days.
Depends on what the railroad is wanting, how often they need helpers and what they have available.
Dave H. Painted side goes up. My website : wnbranch.com
I'd guess that they'd base their decision on how much helper power was needed, and on which of their available locos would meet those requirements.
A locomotive on it's last legs might be good for a few trips, but not for an extended period like a seasonal rush.
I often use helpers on my layout, but none of them are anywhere near the end of their usefulness.
I seem to recall reading of railroads which had scrapped a lot of their own steam, but then turned to buying retired, but not necessarily worn-out, steam, from other roads, due to production delays in the diesels that they had ordered.I'm sure that someone more well-versed in this topic can provide more info.
Wayne
This is a sort of involved thing.
First we should distinguish between two very distinct things that ought to be considered and implemented separately and appropriately. I will use the PRR terms for them to save time.
"Helping" is when you have a train with train resistance and available power functionally incapable of making a ruling grade effectively, and locomotive power is added to allow the train to 'make it' with reasonable reserve for concerns like weather or poor track. (An additional consideration, which I'll return to later, is to add capacity to get the train down a grade, for example with enhanced dynamic braking)
"Snapping" is when you add power to move a train more quickly up a given grade that it might be able to negotiate by itself but much more slowly. This was common practice with passenger trains on the PRR going over the intentionally 'concentrated' grade involving Horse Shoe.
As in the pre-diesel age very different types of steam locomotive will fulfil the operational requirement, you can see why the distinction can be important to make.
Helping isn't something that adds full value to the use of locomotives, particularly steam locomotives. So railroads that would buy helper power 'new' would have some anticipated high utilization... and would purchase accordingly: the early Erie 0-8-8-0s are a good example. On the other hand, a design intended for a use that doesn't 'eventuate' for some reason may be expediently used in either helper service (ahem, Erie Triplex) or hump service (the original NYC Niagara high-pressure 3-cylinder engine, on a railroad with only one really significant snapping grade...)
The 'adaptive reuse' extended into the early diesel era, sometimes with a certain cavalier misunderstanding of how power 'ought' to be used. The usual canonical example is PRR using de-turboed Centipedes as helpers ... with traction-motor blower ducts that didn't fully line up on curves when full cooling was essential, and a huge set of hard-to-replace brakeshoes that suffered when the monster locomotive regularly drifted downgrade...
Remember the dynamic braking thing? UP bought a number of EMD switchers equipped with dynamic brakes to use 'new' on helper grades -- both up and down. This made very good sense except that the switcher trucks were retained, and the engines could not be run 'light' with the dynamic engaged, in part because braking adhesion couldn't be maintained at the desired speed. There is a good UtahRails discussion of this (which we have mentioned here in the past).
Something you might see is the use of large steam used for helping after mainline operations with steam have ended, and the special fuel and water arrangements for them cut back. The problem is that many of these were explicitly designed for horsepower at speed, which would be nifty for snapping except that trains were routinely loaded to within a few tons of helping level, so the locomotives were often worked far outside their sensible horsepower range -- the C&O Alleghenies are often poster children for this kind of abuse, and I think it was common with N&W As (not that the latter couldn't do it, but they were Morgans being used to do Clydesdale work...)
For diesels, you want cheaper, older power that can't be readily used elsewhere... or 'orphan' or specialized power that can be concentrated near a single support base (as I recall being done with Alcos and Baldwins after those builders exited the market for new road power). That might in many cases be false economy if the operational concern is to run trains effectively rather than most cheaply. A wise management will think about what runs the railroad best within cost-effectiveness, and make their helping/snapping decisions accordingly and 'midcourse correct' them as conditions change over the years.
In some cases the decision to assign a locomotive to helper service was based on it being a "mistake" for the railroad, perhaps the most notorious example being the Pennsylvania Railroad's FF1 class electric, "Big Liz," said to be the most powerful single unit electric locomotive ever built (at least at one time), so powerful that when assigned as mainline power in 1917 it had a hasty habit of pulling the couplers right out of the draft gear, back when many freight cars from the late 19th century were still on the rails. It was "demoted" to pusher service for that reason. It was a monster, 140,000 lbs of starting tractive force, and way ahead of its time in terms of overall tractive effort. By the way Big Liz continued her destructive ways in pusher service, and caused incidents where freight cars simply popped off the track in both directions.
Ironically the same thing happened to the Pennsy again 40 years later with their FF2 class electrics, which they purchased, at a bargain price, from the Great Northern where they were Y1 class electric locomotives that the GN no longer needed. Here the problem was not excessive tractive effort to be mainline power, although they were very strong, but they were solid bearing locos not roller bearing and thus not up to the 1950s speeds on the Northeast Corridor. So they generally were used as pushers.
And it happened to the Pennsy again when their huge Baldwin "centipede" diesel electrics turned out to be unsuited to passenger service, were regeared and demoted to freight, and eventually became pushers, or as author Al Stauffer put it "No other class in all dieseldom saw so much service on the rear of trains. Pennsy eventually got their money's worth by working their guts out ...." Pusher service has the advantage of keeping a locomotive close to where it can be serviced. And by then Pennsy steel cabooses could take the strain
And Dr Wayne's point again brings up the Pennsy, which was committed to full dieselizing and had scrapped a few too many of their large freight steam locomotives in the 1950s and ended up acquiring, cheaply, some Santa Fe 2-10-4s for one last hurrah. Of course steam was cheap then which is also why some excellent steam locomotives served out their builder's anticipated lifespan by being acquired by Mexican railroads.
I believe the B&O ended up assigning its huge 2-8-8-4s to helper service at a time when steam in general was being phased out on that railroad. Perhaps the reasoning there was as steam was being phased out, so were steam facilities such as water and coal so keeping the steamers to a defined locale as helpers also helped keeping steam facilities (and work forces) within a defined locale too. That way the B&O got most of the economic value of dieselizing while at the same time getting return on investment from what was their newest (and last) steam purchase.
The only helper service we see here near Milwaukee WI is at Byron Hill on the CN (ex-Wisconsin Central, ex-Soo Line) south of Fond du Lac, where southbound trains struggle to get out of the deep valley of Lake Winnebago. The manned helpers seem to be anything that is just sitting around at the yard and shops, which is mostly modern six axle power anyway.
Dave Nelson
Part of the issue with Liz, as I recall, was synchronous motors that wanted to be at speed, not just power. With only rudimentary slow-speed throttle control like a liquid rheostat. That was the jerking that yanked out the drawbars even with slack action, and the probable reason for cars 'popping'.
Othrt locomotives, notably an Erie Triplex on initial test, were dangerous to contemporary drawbars... I think the test train, of hoppers, broke in three places attempting to get up to Gulf Summit. But we shouldn't forget the steam equivalent to Liz, the thing that soured PRR on simple articulateds, a 2-8-8-0 of enormous proportions and drawbar-plucking TE...
Incidentally the FF2s were bought for very specific service on very specific traffic in a reasonably specific place that was NOT where you'd really expect it. A foreign source of high-grade iron ore was commercialized in the late Fifties, and to get this to mills like Fairless Hills involved very heavy traffic not from the Mesabi to Pittsburgh, but from eastern ports to places like Fairless Hills... so the pushers went to work on the grade at Thorndale, at speeds and over distances their plain bearings could accommodate just fine. Note that the one locomotive rebuilt to look 'faster' with a couple of war-weary F-unit noses was the one that never ran on PRR... perhaps just as well; it's amusing to see the first reactions when railfans see a bulldog nose riding over a rickety single-axle truck.
Note that to my knowledge the FF2s were not used in service other than this, and when the need for them was ended, they were quickly retired and scrapped rather than going to other obvious services.
The ATSF 2-10-4s were another expediency, hired to run on a somewhat rickety line up to Sandusky. What you don't see unless you're looking for it is how badly the locomotives were maintained: in the later months the boilers could be white either with foaming or leaking chemicals. As I recall, when ATSF got them back many were in such poor shape they were summarily retired. (Incidentally these had a longer driver wheelbase than a duplex Q2...)
If selecting a steam locomotive for helper service, tractive effort and driver diameter would seem most important. For a diesel it would be tractive effort and minimum continuous speed. Slogging along at just above walking speed tended to burn up traction motors if one wasn't careful.
hbgatsf ... or can you find more state of the art locomotives? Put another way how do the railroads decide what to use for helpers?
...
or can you find more state of the art locomotives? Put another way how do the railroads decide what to use for helpers?
The requirement, or what's missing from current operations that severely limit revenue generation. In the case of the Norfolk & Western, which placed the last main line steam locomotive built in the USA onto the rails in 1952, it was their vaunted compound traction engine, the Y6b. These were arguably the most advanced steam locomotives, certainly of their type (for drag freights). The Y's of several classes were used for many years to shove/help coal drags over the Blue Ridge.
So, while the source you mentioned in your OP might have been quite factual for a number of applications of helpers, your other surmise that purpose-built engines were often used in helper service is quite correct, at least in the case of the N&W.
NHTXFor a diesel it would be tractive effort and minimum continuous speed.
Generally speaking, diesels come in two gearings, freight and passenger. Any engine that is geared for normal freight operation would be suitable as a helper. Any set of diesel road power could be used as a helper, any engine that is on the front end of the train could be on the rear end too. The front end won't be going any faster than the rear end of the train.
There is loads of pictures of newer steam helping older class locomotives especially around the curve. T1 and M1 in snapper service helping out nearly thirty year old pacifics. There were also thirty year old L1 and K4 on the grades helping new diesels too. Trying to get rid of double heading was one of the reasons for the T1 and the two experimental locomotives, the S1 and S2. Sadly they didn't work out as planned and it turned out some of last fires to be dropped were from nearly fifty year old two cylinder locomotives.
Lines East had plenty of decapods for helper service while lines West had the N1 2-10-2 and others for helper/ snapper service along with the decopods.
In 1912 Baldwin built a single class CC1. An 0-8-8-0 compound locomotive with nearly 98,000 pounds of tractive effort. It didn't work out in head end service and finished it's short ten year life in pusher service. For the times it was considered too powerful for wood frame cars. Then two years later the I1s started showing up in great numbers with the same tractive effort. There were still plenty of wood frame cars. How do you figure it's success over big Liz and the CC1?
Pete.
Thanks for all the information. Many of the examples given have been about steam. Let's talk about diesels.
If you had C30-7s on point of a coal drag in 1983 what range of pushers would you find? Would they be primarily 6 axle units or could you also see 4 axle GPs or road switchers?
Pretty much any 6 axle engine in the 3000-4000 hp range.
1970's-1980's the answer to pretty much any question is "SD40-2".
wrench567 In 1912 Baldwin built a single class CC1. An 0-8-8-0 compound locomotive with nearly 98,000 pounds of tractive effort. It didn't work out in head end service and finished its short ten year life in pusher service.
PRR cut it up in 1932, not 1922, but I have no idea if it had been stored for years and then scrapped in the Depression.
Then two years later the I1s started showing up in great numbers with the same tractive effort. How do you figure its success over big Liz and the CC1?
hbgatsfIf you had C30-7s on point of a coal drag in 1983 what range of pushers would you find? Would they be primarily 6 axle units or could you also see 4 axle GPs or road switchers?
On the other hand I saw a Ore train off the CNW being helped westward on the UP out of Omaha with 3 ex SOU CNW SD40's and 4 UP SW10's out of Council Bluffs yard as helpers on the grade out of the Missouri Valley.
On the Pennsy and PC helper engines after the Centipedes were retired, were for a while the RSD-12's and finally SD40/SD45 Combinations were the preferred helper combination although after Conrail they added SD40-2's, SDP45's and SD50's.
Rick Jesionowski
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The PRR (prostrating myself in the direction of Altoona) had 70 F3's and F7's that were geared (low speed/high tractive effort) for use on the Curve and classed as EH15's. Later they were regeared, reassigned to the General Freight pool and reclassified as EF15/EF15a's.
OvermodThe I1s was a very interesting engine, easily capable of running PRR freight track speed (50mph)
But what did they do to the track? I know PRR used very heavy rail sections and was well ballasted, but still...