Questions about diesel switchers

[CSSHEGEWISCH]

Slugs are strictly low-speed designs that allow additional horsepower to become useful at low speeds. Because of adhesion limits, a high-horsepower design like a GP40 is no more useful in yard service than a GP7. A slug raises the adhesion limit by putting additional weight over additional drivers at the same horsepower. At low speeds, a GP40/slug set becomes the functional equivalent of 2 GP7's. Because a slug has no prime mover, it serves no useful purpose at speeds where the horsepower produced by the slug mother can be used without being affected by adhesion limits.

[DanRaitz]

Calfs were just that "cab-less switchers", you could call them the "B-unit" of the switcher world.
Slugs are a different matter, as they do not have any prime-mover (diesel engine) installed or any means of self-propulsion. They recieve power to run it's traction motors from another diesel.

Dan

[Anonymous]

Speaking of Cows and Calfs.... what exactly was the purpose of a calf? Were the just a cab-less switcher designed for MU lashups in areas where more horsepower was needed, but not the extra cab? Or were they more like today's modern slugs? Lots of weight for extra tractive effort for switching manuevers, but not much else in the way of usefulness?

I notice very few roads use 'calfs' anymore, unless you consider slugs, so they must've been an idea that was outgrown in time.

[Anonymous]

Another perspective on the answers here...

Steam switchers usually had only coupled wheels in order to put all of the loco's weight into the tractive effort.
(When non-driven wheels are added they reduce the tractive effort by the amount of weight they carry...
so why have them?
At the front end it mostly relates to easing transition into curves and also supports some of the front end weight of the design - but some of the front end weight is put onto the leading wheels to ensure they stay on the track... but, contra to what might be inferred from one of the above, leading wheels do not make something more that can be derailed... okay they tend to derail more often than drivers.. that's because they get there first.
Trailing non-driven wheels usually result from boiler and firebox size and design... without a trailing axle or two there would be too much overhang and an imbalance of weight to the rear of the drivers...
why not more drivers to support the back end?
Some firebox designs don't leave space for more drivers. There is a limit to the number of drivers a combination af boiler/cylinders can usefully drive. There is a limit to the number of drivers that can work in a rigid frame on curves of different radii.
The other alternative is to go for an articulated loco... where the designers think this is appropriate... even there you often end up with leading and trailing non-powered axles)

Meanwhile ... back at switchers etc...

If you look at steamers you will see that as a general rule there were four classes of loco. Switchers, Freight, Mixed Traffic and Express.

Switchers had least non-driven axles and (generally) the smallest drivers. They could be pretty massive (I think 0-10-0 was the biggest non-artic) but they were designed for shifting heavy weight slowly. They also rarely went far from their home yard and fuel water supply.

Freight, from local to long distance heavy drag came next in wheel size. Locals tneded to have leading and trailing trucks so that they didn't have to be turned on long spurs. Long haul would turn or Y between trips. Both increased in size to fit their home range/division.

Mixed Traffic (more rare in the US I believe) came between freight and express - I use the word express rather than passenger because there were many smaller branch and suburban passengers that mix things up... and because some freight... reefers especially ran express - A mixed Traffic would haul perishables, milk, mail and reefers but could be bumped up to passenger express for Thanksgiving and other heavy holiday traffic periods.

Express. Not the biggest (that was the big freight) but usually the smartest with the biggest wheels for speed and frame/truck design for getting round the curves smoothly at speed. These were the least good at small moves... like setting cars into a terminal station... they tended to eat fuel and water... so again you didn't want them messing about getting their train out of a carriage yard and hanging about in the terminal. Much better for a switcher to do the donkey work and have the thoroughbred drop onto the train at almost the last minute fully stocked for the journey.

OKAY...

SO DIESELS.

people tend to design by what they know.

So the first express diesels (that developed into the E8s and E9s) were streamlined throroughbreds. Suitable gearing for getting there in a hurry.
It's interesting to notice that right from the start they were effectively "cab ahead" units despite the fact that early freight soon switched from the "cab ahead" F and similar units to long-hood forward hood units. I mention this because we tend to assume that diesels ran long-hood forward following the usual order of boiler-cab on a steamer.... but the Covered Wagons broke this convention right at the start.
There was another advantage to the big passenger diesels... they could run through saving journey time taken by changing steamers. (For newbies steam engines were like stage-coach horses... they could only be run so far before they had to be serviced).

I'm not an expert on what came where, when from whom but my first thoughts on this subject were that Alco distinguished between its "S" switchers, "RS" road switchers and Passenger classes (The DL109s were really fast passenger but called Mixed Traffic to get them by war time building restrictions - same thing happened in the UK with at least the Merchant Navy Class "Spam Cans").

I think that Road Switcher goes a long way to explain what went on and what has developed. The RSs and later GPs - General Purpose - were mules, oxen or medium carthorses. They could switch most yards, work on the main and work the lighter branch lines They were exactly general purpose for switching and road use.

EMD decided that the big diesels with six axles were "SD" = Special Duties... hauling coal and ore... the big stuff needing muscle.
Alco fought back with their Century series but GE pulled the master stroke by designating all their locos "U" = Universal... go anywhere, do anything. One basic breed of locos, one basic set of spares...

Then things got BIGGER... so size for size an early SD now compares to one of the big AC things in the way that a GP used to compare to it.

As has been noted there is still demand for the small switchers or small GPs. The locos not much mentioned here are the small industrials and critters. They still quietly do their bit where appropriate.

Also, a completely different issue... passenger diesels have seperated off into a completely different line of development.

Q2 People have covered where switchers appear. the simple answer is "where they are most suitable and available.
Q3 Horse Power... Also answered.But it's not just raw horsepower... it's getting the power on the rail... so there have been devekopments in traction control and there are slugs. There are also DPUs (Distributed Power Units)... which also factor into the whole equation of what sort of loco to do the job.

BUT Qs 2&3... what happens is a mix of what is available (including what cash is available), what is best suited ... and that means what power is needed, track conditions, loads and all sorts. The solution is not just switchers, GPs, SDs or modern big power but what will get the right amount of power down most cost effectively.

If a job is best haued by a pair of ACs... say a unit coal train... it may also be appropriate for them to stay on the train for the slow crawl to load or unload on the move. Elsewhere it may be appropriate for a switcher to dawdle off along the main with a couple of cars.

Then there's cow-calf combination, slugs and things...

Hope this helps.

Er... what I haven't said but others have commented on is that diesels get different wheel sizes to a small degree but lots of different gear ratios and turbos or not turbos. these don't show up in the same way that different sized drivers and wheel arrangements did on steamers. This led very rapidly to steam fans saying that diesels were boring because they all looked the same. The biggest give away is often in special trucks... and that gets knobbled by RRs trading in trucks... Fuel tank size and dynamic brakes make a difference... but never as much as between a heavy freight and a light passenger steamer.

[f14aplusfl]

First off, its your railroad so you can do whatever you want. [:P] It also depends on what your modeling.

A number of railroads used SD38s for hump yard power thanks to their tractive effort for pushing frieght cars over the hump to be sorted via switches moved by our friend Issac Newton (gravity). At other times, a railroad might used what's readily available and on hand. Granted you probably won't want to use (or see often) a 9-44CW or SD70M for yard service but if thats what's available and there are cars that need to be switched, then the railroad will use them. Some railroads like the Florida East Coast Railway no longer operate switchers, in their place, you can find either GP38-2s or GP40/-2/-3s in there place. Statistically speaking you're more likely to get a GP40 model... and I think there is a GP40 outfitted with remote control equipment. I don't know if CSX uses remote control equipment but sometimes a switcher due to its smaller size, doesn't have the space for it.

Side note: To save money or due to the the length of the run in which a railroad bought a locomotive.... they might not have toliets on board.

[dbradley]

Just a couple cents worth. The cyclopedia volume 2 states that and SW-1200 has was no lighter than a GP-9, but tighter turning. The New Haven, which I model, had souped up SW-1200's with full length hand rails, MU and flexicoil trucks for higher speeds and tracking over the road. One other thing that I understand restricted there use, was there lack of toilet facilities on board. I don't know if that was a state or railroad mandate.
I know more than a couple of cents worth, Sorry.

[LVJJJ]

For switching up here in the extreme pacific northwest (up against the Canadian border Blaine, Bellingham, etc.), BNSF uses old GP-38's, GP-30's, even seen some GP-9's, all rebuilt of course. Haven't seen a "real" switcher in this area for decades. (been here since 1961). Whereas before the merger, all we got to see up here was green & black, now we have a rainbow of colors which makes for some very interesting lash-ups. In fact, I have a GP-30, N gage loco with the same road number as one of the old GP-30's running around up here (2817 I think). Now that's exciting, huh!! Larry in Blaine.

[CSSHEGEWISCH]

QUOTE: Originally posted by AltonFan

AIUI, new emissions standards being phased in over the next ten or so years is forcing the railroads to start considering purchasing new switchers to meet those standards.

California and Texas are just leading the way on this issue. The Houston metro area is under an EPA order to clean up their emissions drastically (Houston rivals Los Angeles for dirty air) and this also involves industry, such as railroads, construction, factory and refinery emissions, etc. Hence the need for low-emission switchers and light road switchers. California has long been ahead of the rest of the country on emissions issues.

[AltonFan]

AIUI, new emissions standards being phased in over the next ten or so years is forcing the railroads to start considering purchasing new switchers to meet those standards.

[CSSHEGEWISCH]

A good idea for Green Goats would be to go right to the source:

http://www.railpower.com

You can even find more specs on their whole product line on that site.

[Anonymous]

Speaking of all these Green Goats, I've never seen one. Can somebody post up a link to some pics?

[Anonymous]

The GP30 is 2,250 HP, and the SD40-2 is 3,000 - both are roughly 500 HP per axle, so they should be very similar on a per-axle basis.

The problem, as you've noted, is that the 6 axle locos tend to derail when used on switching duties, especially in industiral areas with tight curves. So a trio of GP38's (2,000 HP each) or GP30's would typically be better for most switching assignments that a pair of SD40-2's.

As for the Green Goats, the railroads are snapping them up because of reduced fuel consumption (cost), emissions (regulatory compliance), and because the price is definitely right - don't know about elsewhere, but from my reading it seems they are basically free in Texas and California - the states are buying them for the railroads with pollution control funds.

From the looks of things, we'll be seeing lots of green goats in the future.

[Anonymous]

I know that I just finished some switching this 4am this morning and we use a GP30 and a SD40-2 MU'd together in our yard. The GP30 is horrible at only about 2000hp. The SD40-2 is great at I think 3000 or 4000HP (have to look at the switchlist or research it because I am writing this after working 12 hours). We regularly send out 2 or 3 SD40-2's as local power for local industry switching. We can not utilize 6 axle units in some areas of the yard, and in alot of the local industries. They will derail, usually the second or third unit on the ground at the tight switches and curves.

[SSW9389]

This is only partially true. To answer air pollution requirements in California UP is purchasing a number of the genset switchers. We will have to see if this trend spreads across the country.

This past summer a Green Goat pair tested at O'Bannon, Kentucky home of the Ford Truck Plant on Louisville's east side. That site has some very heavy switching with long cuts of cars. The Green Goats seemed to do all right in this service, but it was only a test. After they moved on it was back to the GP40-2/Road Mate sets that have been prevalent at this site for years. [;)]

QUOTE: Originally posted by LongIslandTom

I think the fact that there is a glut of 4-axle power out there right now also makes it hard to buy a new-built switcher.. All the mega-mergers, streamlining and buying of new high-powered 6-axle units have flooded the used locomotive market with Geeps and GE Dash-whatever B's of all types, and the prevalence of spare parts and infrastructure availability for these Geeps makes them easy to support .

It would be cheaper for a railroad today to just pick up a second-hand or refurbished Geep than to buy a new-built switcher... At least until these second-hands and refurbished locos finally reach the end of their useful lives, say maybe 20 years or so from now.

[Leon Silverman]

The usefull life of a locomotive is a metallugical issue determined by the fatigue life of the locomotive's chassis. Prime movers, generators, controls, traction motors and trucks can be replaced. Re-welding a cracked frame with confidence that it will hold together in service is another matter. This is what ultimately forced all of the GG-1s to be retired.
Fatigue life becomes an issue for over the road engines that are run at full power most of the time. The loadings on a switcher-duty locomotive may not be consistently high enough or long enough to induce fatigue failures.
FYI: fatigue occurs at stress levels below the yield point of metals but results from cyclic loadings that do not allow the material to "adjust" to the load.

[Anonymous]

I think the fact that there is a glut of 4-axle power out there right now also makes it hard to buy a new-built switcher.. All the mega-mergers, streamlining and buying of new high-powered 6-axle units have flooded the used locomotive market with Geeps and GE Dash-whatever B's of all types, and the prevalence of spare parts and infrastructure availability for these Geeps makes them easy to support .

It would be cheaper for a railroad today to just pick up a second-hand or refurbished Geep than to buy a new-built switcher... At least until these second-hands and refurbished locos finally reach the end of their useful lives, say maybe 20 years or so from now.

[CSSHEGEWISCH]

GE has never built much in the way of switchers beyond industrial designs and EMD has dropped switchers mostly because the market has dried up for what was a low-margin product.

MPI, Railpower and possibly NRE are poised to become niche manufacturers in the switcher market especially with the demand for low-emission locomotives.

[bogp40]

QUOTE: Originally posted by jshrade
Oh, and for any CSX buffs out there, anybody know where I could see switchers in Georgia?

Thanks!

CSX has so many GP40s and dash2s on the roster left from the massive amount of Chessie units, I see these switching out many of the major yards.
This is a bit ironic that you asked this first and want to see CSX yards. This may not be the case with each and every CSX yard, but what a powerful unit to switch a yard. I can't help with any hot spots in Georgia though.
Bob K.

[wjstix]

I wasn't asking if there was an article written on it - there was - I just couldn't recall if it was in RMC or Railfan and Railroad or ??

I did find it now:

Railfan and Railroad, May 2006, pg. 63 "VANISHING SWITCHERS" in Jim Boyd's "Camerabag" column.

"There hasn't been a new switcher put together by a major builder in more than a decade, and veteran SD-70MAC's won't make good yard switchers ten years from now."

[:D]

[Newyorkcentralfan]

wjstix wrote:

"Was it Railfan and Railroad that had a small article recently about switchers?? Anyway, the article pointed out that there haven't been any new switchers made since the early seventies, and that it will be interesting to see if railroads will start to order new switchers when the current ones are retired, or if they'll 'make do' with something else."

I doubt it since it's not true.

EMD built SW-1001, MP-15AC, MP-15DC and MP-15Ts into the late eighties.

In the nineties EMD catalogued switchers.

Eric

[Anonymous]

QUOTE: Originally posted by tomikawaTT



Now substitute car for bucket, yard switcher for pickup truck, road switcher for bobtail and your favorite 6-axle superpower for freeway-capable tractor and you should have the picture. 18-wheelers don't make good delivery trucks, and pickups aren't practical for handling maximum-tonnage loads to interstate distances on a freeway. The same reasoning applies to SD70MAC's and SW1500's.

Chuck

I don't know why my complicated mind wouldn't let me think of the same thing, but that makes perfect sense, and is a GREAT explanation!

Thanks for all the replies guys! Now I know better how and where to operate the switchers on my layout!

[Jetrock]

Plenty of short lines used switching engines for road engines--many used diminuitive things like General Electric 44-tonners or EMD SW1s for mainline freight service where runs and trains were short.

Another advantage to small diesels is that they can be linked together for more power: MU four 1500-HP locomotives together and you have what is effectively a 6000-HP locomotive with a single crew, but if all you need is one 1500 HP locomotive for a smaller job, you can save yourself three-quarters of the fuel and maintenance costs.

There are new (well, technically refurbed old chassis, but effectively new) switchers being made: the "Green Goat" line of hybrid diesel-electrics.

Industries sometimes need something with just enough muscle to shuffle a couple of cars around. A small industrial switcher is ideal for this, and doesn't break the bank: depending on the size of the industry, a B-B switcher of various sorts, on down to tiny four-wheel switchers like the GE 25-tonners or, more recently, small Trackmobiles that can pull a car or two and have ground wheels that allow them to run on or off the rails. If you're an industry that only has to shuffle a car or two, why buy something the size of a road engine with an underpowered motor when a tiny industrial switcher will do the job in a fraction of the space and cost?

[tomikawaTT]

To explain why a railroad needs different-size locos with different characteristics, let's compare the operation of a small-scale motor-vehicle-oriented distributor:

Say you have a warehouse in a seaport city that deals in buckets of sand from some middle-eastern country. The sand arrives by ship, in buckets. All you have to do is get them to the customers.

For in-town deliveries, you would want to use a pickup, or a small panel van. Only a few buckets at a time, and the vehicle is well suited to the frequent stops and generally low speed of in-town driving.

Some of the buckets have to go to a couple of towns a few miles down a country road. For this service, a 24 foot bobtail, 2-3 ton capacity, is the best compromise between over the road speed and frequent stops to make deliveries.

A thousand buckets have to go to another distributor several states away. They leave in a box trailer behind a freeway-capable tractor, ready to add to the stream of 18-wheelers that really should be piggybacked.

Now substitute car for bucket, yard switcher for pickup truck, road switcher for bobtail and your favorite 6-axle superpower for freeway-capable tractor and you should have the picture. 18-wheelers don't make good delivery trucks, and pickups aren't practical for handling maximum-tonnage loads to interstate distances on a freeway. The same reasoning applies to SD70MAC's and SW1500's.

Chuck

[emdgp92]

Some railroads used switchers in mainline service. The Montour RR (no longer in operation) used their SW7s and '9s on coal trains here in SW PA. The SWs were well suited to the light rail and curves of the lines.

[CSSHEGEWISCH]

More horsepower is necessary to move a given tonnage at road speeds. Since nothing is moving very fast in a yard, less hp is needed to move that tonnage around within yard limits. This is a reason why slugs are more likely to be found in yards, they provide additional low-speed tractive effort.

[Anonymous]

I heard of some de-turboing and de-rating of the EMD 50's-series locos on the NS...

Most prominently, they took the GP50s and de-turboed and -rated them, so now they are called GP38-3's by the NS:


I can be wrong, but I hear they are also derating SD50's too..

[twcenterprises]

QUOTE: Originally posted by rayw46

Actually LongIandTom, Norfolk Southern regularly uses 3000 horsepower SD40-2's in switcher service, less the turbocharger. There are a bunch (is that a prototype railroad term) of them, along with GP38-2,s, assigned to the Gainesville, Georgia yard which services several Feed Mills, Cargill Food and a variety of other industries up and down the line.

Where did you "find" this info? I wasn't aware that NS de-turbo'd anything, since these units could be called up for road duty if needed. I've seen that happen in Gainesvile late one night, when a train had a malfunctioning "motor" (loco), and needed to swap some power. 15 minutes later and they were back on the road.

BTW, where do you live, we can get together sometime. Email me if interested.

Brad

[Anonymous]

QUOTE: Originally posted by rayw46

Actually LongIandTom, Norfolk Southern regularly uses 3000 horsepower SD40-2's in switcher service, less the turbocharger.

SD40-2's less the turbocharger, what does that mean? An SD40-2 that has been de-rated by removing the turbocharger?

If that's the case, it ain't an SD40-2 any longer! [:p]

IIRC, the normally-aspirated (non-turbo) version of the SD40-2 16-cylinder prime mover generates only a bit over 2000hp (which is what I think the SD38-2 is).

[wjstix]

Was it Railfan and Railroad that had a small article recently about switchers?? Anyway, the article pointed out that there haven't been any new switchers made since the early seventies, and that it will be interesting to see if railroads will start to order new switchers when the current ones are retired, or if they'll 'make do' with something else.

I suppose with diesels it was partly a carryover from steam. At slow speeds you didn't need a pilot axle to navigate points (in fact it could be one more thing that could derail) so many early switchers were 2-6-0 or 2-8-0 engines with the pony truck removed. Later, builders started making switch engines like 0-6-0's and 0-8-0's. At slow speeds, you could also use sharper curves, so it also favored the smaller engines.