f14aplusfl wrote: "If a locomotive with a low tractive effort is coupled with locomotives having a substantially higher tractive effort, the wheels on the lower rated locomotive will begin slipping while accelerating a heavy train long before the other locomotives. This is why you will never see an SW1500, which has a tractive effort rating of only 42,000lbs, running in a consist of road units such as the SD40-2, which has a rating of 83,000lbs. In such a situation, the SW1500 will be shut down and in tow. So modelers, take this into consideration when assigning locomotives to your trains." From: Conrail Cyclopedia EMD SD40-2: Prototype Info
"If a locomotive with a low tractive effort is coupled with locomotives having a substantially higher tractive effort, the wheels on the lower rated locomotive will begin slipping while accelerating a heavy train long before the other locomotives. This is why you will never see an SW1500, which has a tractive effort rating of only 42,000lbs, running in a consist of road units such as the SD40-2, which has a rating of 83,000lbs. In such a situation, the SW1500 will be shut down and in tow. So modelers, take this into consideration when assigning locomotives to your trains."
From: Conrail Cyclopedia EMD SD40-2: Prototype Info
I don't know if I can accept your theory. I don't believe it could only be a function of tractive effort (which was equal to one-forth of the weight on powered axles). A more plausible theory, and I don't know if this is true either, would be the ratio between horsepower and weight per powered axle.
Let's compare 3 early Southern Pacific road switchers: the SW900, SD9 and GP9. (Yes, the SP used SW900s as roadswitchers -- they put train number boards on them.)
The SW900 (900 hp, 232,600 lb. weight-on-drivers, 4 axles, 58,150 lb. tractive effort) had a 258 pounds per horsepower.
The SD9 (1750 hp, 328,340 lb. weight-on-drivers, 6 axles, 82,085 lb. tractive effort) had 188 pounds per horsepower.
The GP9 (1750 hp, 248,420 lb. weight-on-drivers, 4 axles, 62,105 lb. tractive effort) had 142 pounds per horsepower.
Even though the GP9 and SW900 had the nearly the same tractive effort, the GP9 would slip its drivers before the SW900 if one accepts the axle weight/horsepower theory. Similarly, the SD9 with 41% more TE, would slip before the SW900 also.
Mark
Hello Mike,
That sounds like an interesting train,what livery were the SW1200s painted in?and what sort of cars were used for the steam generator?
Malcolm.
Hello:
During the early 60s, CN reportedly occasionally used an SW1200RS on the passenger train between Jasper and Prince Rupert via Prince George. It was a relatively short train of conventional cars at the time. Steam heat was provided by one of CN's steam generator cars.
However, at the time CN considered an SW1200RS (a GMD SW1200 switcher modified with flexicoil road trucks, larger fuel tank, MU and road number boards) to be a road switcher and not a switcher. Some SW1200RSs are still around on CN's roster, but they are definitely used as switchers now.
There was a lot of variation in the consist of that train during the later 50s to 60s. RDCs were also tried before they settled back into using conventional equipment on that run. That train still runs today as VIA's Skeena with run of the mill F40PHs.
Mike
You might see them on a transfer run... i.e. taking passenger cars from the yard to the car shop for inspection. Not sure if this helps but I think a locomotive strickly used as a "yard switcher locomotive" would be a last resort. Also keep in mind road locomotives may have some equipment for signals and stuff they may or may not be mounted in those used strictly for yard use and vise versa. In that case, a yard switcher may not be cleared to operate on the mainline unless another unit is in the lead. While on that topic, yard switchers may not be mu capable. Additional units maybe needed depending on the weight and length of the train. It is an issue of tractive effort. Wheel-slippage is such an important issue and railroads assign locomotives of similar tractive efforts to a train.
Interesting notion that,here in the UK some of our heritage railways use 4 and 6 wheel shunters (switchers) steam and diesel doing brake van (like a 4 wheel bobber) runs but under our health and safety laws riding in a gondola type wagon is forbidden.
http://delray1967.shutterfly.com/pictures/5
SEMI Free-Mo@groups.io
There are many examples of switchers being used for branchline passenger service. Some examples are the Wabash which used a lima switcher on it's Columbia (missouri) branch line and the Pennsy used baldwin switchers on some of it's commuter branch lines. Also, page 22 of this months Model Railroader shows a Frisco baldwin switcher pulling a mixed train.
Dale.
Hello Paul,
Thank you for your reply to my question on using switchers on passenger trains.You bought up another favourite subject of mine,doodlebugs.I kitbashed a couple from the Roundhouse Harriman coach.For M1 I used a combine and cut off the end bulkheads to above the floor and used the inside bulkheads as the cabfront and opened up a window in the side for the engineerand use 1/2 mm evergreen clapboard as radiator shutter on t.I hope you liked my idesahe front ,then cut the roof above the motor area and fiited it with a flat roof with plastic tube for the stacks and details associates captop fans on square tube section and a hole was cut in the floor for a SPUD and a very large heavy steel weight was added to slow the SPUD,it sounds complicated but it worked.I also made a combine/caboose from another Harriman by cutting a section of roof to accommodate an Athearn wide vision cupola near the baggage doors again an interesting looking coach which goes well with a mixed train .I hope you liked my ideas.
Regards,Malcolm.
As referenced above the Maryland and Pennsylvania used their NW2 (and possible their SW9) for passenger duty. According to Hilton's book, this was done on Saturdays when they weren't being used for freights. This was done to save money as it was cheaper to use the diesels than the gas electrics. During the week they used their gas electrics (they had 2). The NW2 was a standard EMD switcher, but was used as a road engine on the Ma&Pa. Prior to Oct 1951 there were two round trip passenger cars a day, and when one of the gas electrics was unavailable during the week they used steam, a 4-4-0 or a 4-6-0.
Interestingly, the gas electric pulled a mail/baggage car, but the diesel had to pull both the mail/baggage and a coach.
Enjoy
Paul
Well we get into a problem of "what is a switcher??". The NW-5 and RS-1 (and you might argue, the MP-15) were road switchers not switch engines. "RS = Road Switcher". The RS-1 began production in 1941 and I think from the outset could be ordered with a steam generator for passenger service. The NW-5 was basically an early road switcher - an NW-2 type switcher with an additional section behind the cab for the steam generator.
Classic Trains had something a few issues back on a I think an 0-6-0 being used on an emergency passenger run, because it had the connections for passenger car steam heat (it was used to switch passenger cars in a terminal) and was the only engine available due to a blizzard. But such uses of a steam or diesel switcher (not road switcher) on passenger trains would be very very rare and isolated incidents.
The only examples I have known first-hand are on tourist railroads, as in the "sawmill line" in eastern Victoria Island (steam-powered sawmill there) and at Sacramento, California along the Sacramento River. If you include geared locomotives, there are lots more in "my neighborhood." Get real: how about 4-4-0, 2-6-0, 2-8-0, and 2-6-2 if you're looking for "lower-end" steam locomotives? Forget diesel-electric switchers as passenger locomotives, at least before SD-7s with boilers (as used on the Northwestern Pacifiic), and similarly-equipped SD-9s and GP-7/9s elsewhere, or maybe some Baldwin AS-616s in mixed passenger/freight service, and little else later on.
LIRR regularly assigned MP15AC's to suburban trains on the Oyster Bay branch. HEP was supplied by the power/cab car on the other end.
EMD built some NW-5 Switchers that were sort of a predessor of the GP-7 and BL-1. It also competed with the Alco RS-1.
These switchers were equiped with steam generators and Blomberg Road Trucks. I believe that EMD made 13 of these. 10 to the Great Northers, 2 to the Detroit Union Terminal, and 1 to the Southern.
Rick
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BillD53A wrote:I -THINK- I'm not sure but I THINK LIRR used MP15s or SW 15s or whatever as power on commuters. But I am not sure.
Yes, indeed, they have MP15AC's that are occasionally used on commuter trains.....some are even wired to provide head-end power.
Bill
"Never try to teach a pig to sing. It wastes your time and annoys the pig"
The gearing was normally the same as on a regular freight engine and most diesel switchers I have seen have top speeds in the 50 mph range. The challenge is acceleration. A GP7 has 375 hp/axle. An E8 has 500 hp/axle. A typical 1000 hp switcher has only 250 hp/axle. It can get the train up to 50 mph, but in a commuter territory not before it reaches the next station.
Dave H.
Dave H. Painted side goes up. My website : wnbranch.com
The Maryland and Pennsylvania railroad used a EMD switcher as passenger power. There was no need for a steam boiler and the speeds were less than 25 mph anyhow.
They did keep a doodlebug and one steam engine on hand in case the Switcher needed shop work. This arrangement lasted well into the 50's
The Reading tried an NW2 as a passenger engine, but it lacked the hp to accelerate fast enough to maintain a schedule.
Baldwin made the RS12, a S12 switcher with a short hood for a steam generator. that was used on many branchline applications. They ended their days switching the coach yards in Amtrak facilities. An RS12 model is made by Stewart.
It also depends on how you define a "yard switcher" since RS1,2,3 GP7, 9, H24-66's have all been bought/used as yard engines and all have been used in passenger service.