Hello everybody,
I find it curious that centre cab switchers never became very popular here in North America, Alco had a version: http://www.railpictures.net/viewphoto.php?id=389733, of course there were numerous GE switchers which were build in the 40's and 50's and then there is a gen set engine http://www.railpictures.net/viewphoto.php?id=389817&nseq=0 which is also a center cab. In comparison to the number of regular end cab switchers the difference is huge.
So what are the advantages of having the cab at one end of the locomotive for switching?
Frank
Please note: I have never operated a locomotive and am just plain curious
"If you need a helping hand, you'll find one at the end of your arm."
An interesting question. Of course from the standpoint of the crew any engine without a toilet facility was unpopular. that but applies to end cab as well as center cab switchers particularly if used in main line duty.
The GE 44 ton and 45 ton switchers were extremely popular with industries, less so with common carrier railroads. There were also center cab transfer locomotives, some of the them truly monster in size, that the Pennsy and some other railroads used. And of course in a sense the Pennsy GG1 was a center cab engine, although anything but a switcher, and there were other center cab electrics.
Dave Nelson
A problem I've seen cited with Alco's design was unequal weight distribution. The accessories and ballast at the opposite end didn't compensate for the weight of the 251 at the other end, causing traction issues.
With a single heavy duty diesel engine, like most class 1 switchers had, it doesn't make any sense to make it be a centercab. The machine becomes bigger than it needs to be and you have weight distribution issues. Things like GE's popular 44 tonner had two smaller diesel engines, making a centercab practical.
About the only area where they made much of an impact on larger railroads were as heavy duty transfer locomotives with two large diesel engines to get a locomotive with 2000-2500 HP in an era where 1,500 was about the most you could get from a single diesel engine (with most switchers being 1,000hp or less). But EMD's response with cow/calf (And sometimes another calf) switchers with the necessary power and improved visibility compared to two traditional switchers quickly killed that concept off almost before it started. The Pennsy bought nearly 50 such machines from Lima and Baldwin 60 years ago for the most notable user of large centercab transfer locomotives.
In effect, the PRR GG1 was considered a center cab! But, for the most part, center cabs were very effective in yard services where moves were made often in each direction; short lines loved them, too. But I think Americans always felt the cab was at the end of the powerhouse, that Camelbacks had safety and communication problems, that diesels should be the same as diesels...the concept of short nosed running was a hard sell to both managment and crews for that matter. Then, as the size of cars grew,the abilty to see above the cars was negated, too.
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Why couldn't a center cab have a toilet?
Kind of surprised that no one has mentioned the Pennsy's (PRR) fleet of large center cabs built by Baldwin .
2400 HP, C-C trucked, Center Cab, model RT-624,built between 1950-1952. Only about 24 or 25 were built(?). Pennsylvania RR operated them more or less form Philadelphia west and Altoona east. It was intended for heavy drag freight service. Its' 74 feet of length packed in 2 prime movers (606SC engines,both turbo charged) to produce 106,200pounds of starting traction and some 76000 pounds continuous.
PRR had 23 and Minneapolis,Northfield & Southern had a single 1, ( Currently, its' predecessor type a DT-6-6-2000 is housed at the Illinois Railway Museum). (none of the RT624s were preserved.)
linked photo: http://yardlimit.railfan.net/baldwin/dt66-2000/trona-51.jpg
They couldn't decide which would be the fireman's side and which would be the engineer's side so they couldn't decide which end was the short hood.
Exraordinarily appropriate that this inquiry came from "***," because there's a connection to German imports assosciated with objections to the example eng: the Century 415, Alco's V-8 center-cab slightly off-set to one end. In the other hood was auxiliary equipment such as a driveshaft driven air-compresser and if memory serves the main generater.
Digressing, cited already have been engines which under the cab, without or with "facilities" had machinery which was electrically but not mechanically connected physically between hoods. under the cab: frame, fuel tank, cables......but not a 1000 rpm drive-shaft which had 1500 hp twirl in it.
Imagine controlling that thing sitting about four feet away from it....it's not enclosed in armor plate.
The German connection: a sand-house myth held that a Krausse-Maffei diesel- hydraulic, trailing unit, in Run eight underload had a drive-shaft failure and auguered almost everything in the (vacant) cab.
Referral is to the drive shafts under the cab floor. The KM's trucks under the cab floor were 1800 hp drive shafts, torque converters, gear-boxes....stuff that after a failure you would not want traveling through your chair.
The Alco DH643 inspired the same degree of fear-factor. The other- mentioned center-cabs have none of it.
The reason center-cabs have not been popular is that generally a single diesel locomotive has one prime mover, and the cab and prime mover cannot occupy the same space. So the choice is either an end-cab, and there were and are lots of end-cab switchers, or a short -hood-long-hood switcher, with prime mover in the long hood, and accessories, including the toilet, in the short hood.
In addition to the prime mover in the "long hood" there are other components connected to the shaft of the prime mover: air compressor, traction motor fans, generator and auxiliary generator. Since all of those are on a common shaft, it is best to keep them close. The cab at one end also makes it nice for visibility, at least you can see the brakeman and couplers on one end of the locomotive.
The little 44/45 tonners often use two diesels (one on each end) and each of these has a generator and perhaps an air compressor on its shaft. It is easier to design a center cab when the machinery can be divided in two sections like this.
High short hoods make absolutely no sense, except if you feel insecure about looking out the window. But the tradition of steam engine design was a hard habit to break.
High short hoods were used for things like steam generators and the all important potty. BLW used them for a extra 900 gal fuel tank. Many early road switchers were set up to run long hood forward so the short hood's height didn't matter. ( Just saw a NS GP38-2 set up this way, in Toledo, was a former Southern unit.)
I think end cabs won out because they are easier to design, build and mataine as compaired to a center cab design. End cab puts all the heavy machinery together and all the control conections at one end of the cab. That way one nis not working over, around or through the cab.
Tim
Keep in mind the center-cab units like the 44 and 45 ton GE's and some smaller units were intended for specific use. Federal regs at the time specified that any locomotive over the 45 ton weight had to have two crewmen. Well, that's a bit silly for locomotives being used in short-haul-industrial application, so the center cab GE's filled a need. They really weren't intended for over-the -road use, especially since bigger and better units were available.
Also keep in mind that he 44 could be thought of as dieselized versions of GE's steeple cab electric locomotives - a design that started with the Black Mariah from 1894. On the flip side, the electric switchers built for the Niagara Junction looked liked electric 44 tonners. It was very easy to divide the auxiliary equipment into the two end hoods on an electric and the steeple cab gave good visibility in both directions. While most of the GE steeple cab switchers went to interurban and industrial lines, the Milwaukee bought some for their electric operations.
- Erik
There also was conflicting pholosophies on reverse running. By practice, because of steam locomotives, the engineer was on the right and the long boiler was ahead of him. With diesels and the abilities to run equal in reverse, it was thought that there would be no need to turnn the locomotive, thus, a steeple or center cab sounded great but put the engineer on the "wrong" side when changing direction and many balked. A cab with dual control stand, one on each side, was considered and in fact applied on many road swtichers but deemed a luxury and thus too costly. Chop nose or low short hood seemed to fill the bill satisfactorily until units became bigger and bigger with full width cabs and bodyies. SO with switchers, cab on end, especially if no short hood, was good and single cab with a long and short hood was acceptable (especially if equipped with dual controls) for road swithcers followed by the chop nose for the norm. I believe the engineer having to twist or work behind his back, etc. were all ergonomically a no, no, especially on road assignments: too uncomfortable for too long a time. Of course, management also tried to not purchase toilets for short hoods, too.
thank you for all the great replies. The points brought up are very interesting and thought provoking. The reasons for this style of locomotive not being successful here in America is interesting and does make sense.
Thank you for the replies
One item that has not really been mentioned or explored. No matter where the cab is located on the car-body - the engineers vision is obscured on the off side. When manned locomotives are used in switching they are oriented so that the engineer can have a line of vision for most of the activities that his ground crew are performing. By being able to see the ground crew hand signals can be used for the majority of the switching moves necessary.
No matter if the locomotive has a center cab or end cab - the engineer is on one side of the locomotive or the other. Even if the cab has dual operating controls on either side of the locomotive, the engineer must observe proper procedures in changing from one control stand to the other as only one control stand can be operative at any single point in time.
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There were a couple of reasonably successful center cab diesel-hydraulics built in Japan. The smaller DD13 class had two 600 HP power plants, while the larger (and faster) DD51 class had 1000 HP engines. Each engine drove one truck through Cardan shafts and gears. There was no mechanical connection between the two ends.
I've never been in the cab of either, so I have no idea about whether they have one control stand or two.
Chuck
The C415 was advertised as giving the engineer 360 degree visibility over both hoods of the unit. In the Rock Island's case the cab could not be that high so as to fit under 12th St bridge in the intermodal yard.
The next problem, as previously mentioned was the near 18 ft (IIRC) drive shaft. The RI enginemen did not have the fear of failure, guess we never thought of it. Having the radiators in the rear meant having long water pipe runs. The vibration of the long drive shaft did nothing but help promote leakage. Also the electrical cabinet was in the rear or the cab, the wire salesman sure made out good selling those umpteen extra yards of wire.
All told the C415, in my opinion, was a senseless design. Alco should have known better. Had it been designed as a conventional end cab switcher, or a road switcher (think GP15) Alco might have had something.
Dick Haave
rrboomer The C415 was advertised as giving the engineer 360 degree visibility over both hoods of the unit. In the Rock Island's case the cab could not be that high so as to fit under 12th St bridge in the intermodal yard. The next problem, as previously mentioned was the near 18 ft (IIRC) drive shaft. The RI enginemen did not have the fear of failure, guess we never thought of it. Having the radiators in the rear meant having long water pipe runs. The vibration of the long drive shaft did nothing but help promote leakage. Also the electrical cabinet was in the rear or the cab, the wire salesman sure made out good selling those umpteen extra yards of wire. All told the C415, in my opinion, was a senseless design. Alco should have known better. Had it been designed as a conventional end cab switcher, or a road switcher (think GP15) Alco might have had something. Dick Haave
And again the next problem was that cars got bigger and bigger so that steeple and center cabs did not offer any advantage.
As far as the C415 is concerned, I will admit that it was a poor design for most of the reasons mentioned in prior posts. However, keep in mind that Alco was attempting to break back into the switcher market (the last previous T6's had been built in 1959) and they may have been looking for something that had an edge over the SW1500. Given Alco's poor rep as a result of the 244 engine, I'm not sure that an endcab design would have sold much better.
Well, as an engineer, those high noses are a pain to see over. Operating long nose forward is a pain, and certain cab would mean a tall long nose all the time. Yipes!
Having run both types (Alco S-1) and Whitcomb Center Cab, most of our engineers at the Hoosier Valley prefer the Whitcomb in switching and the Alco over the road. As to which end is the front? Look at the side of any locomotive. There is an F painted on the front end. Train crews have to look at it before starting to know what hand signals to give. Yes, that does give problems during the day as people get tired and forget. Center cabs really heighten that problem, but it still occurs even with a cab at the end of the locomotive.
This was a great topic. But there are several more points I would like to add.
The EJ & E had two powerhouse center cabs (from Baldwin I believe) that lasted well into the late 80's. Engineers loved them for the transfer jobs the "J" was famous for. One broke down and has been canabilized for the other, but I believe it is still in northern illinois somewhere. Toilets were always available.... in the bushes near the mainline. Sorry
The major complaint I recall from engineers about center-cab design, was not "fear factor" or line-of-site, or even toilets. It was HEAT !
In the summer months... sitting between to 567's (or such) with no comfort cabs having been thought of yet... temperatures in the cabs got above 110 degrees. At least in a end of unit cab... you got air movement !
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They were popular on the Minneapolis, Northfield & Southern Ry. They had dual controls so the engineer could run them from either side. They would not M.U., but the MN&S sometimes double-headed them with two engineers.
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