JustWonderin' PNWRMNMI am 99% sure the trailing tonnage answer is incorrect. Light refers to some combination of total locomotive weight and/or weight on drivers. Since I'm relatively ignorant on this topic, I wasn't going to challenge the original answer, but I thought I'd read somewhere that, as you say, "light" related to wheel loading and that light engines were intended to be used on less robust track.
PNWRMNMI am 99% sure the trailing tonnage answer is incorrect. Light refers to some combination of total locomotive weight and/or weight on drivers.
Since I'm relatively ignorant on this topic, I wasn't going to challenge the original answer, but I thought I'd read somewhere that, as you say, "light" related to wheel loading and that light engines were intended to be used on less robust track.
Just,
There are really two senses to the issue of "light" locomotives. In steam it is reasonably common to see references to light or heavy 2-8-0, 4-6-2 and 2-8-2. I think what you are seeing is a tendency for size and weight to increase over time, holding wheel arrangements constant. I think this had more to do with technological improvement and loco growth over time. Having said that, yes the track had to be able to support heavier weight and axle loadings. Rail weight increased from 50 pound per yard to 100 pound per yard between 1865 and 1915. Since rails are a beam, their stiffness increased roughly as the square of the increase in weight, so 100 pound rail was about 4 times stiffer than the 50#. Also this period includes change from iron to steel rail.
The other sense is that because the track was not maintained, usually being light rail on generally rotten ties, management desired to limit the axle loading rather than fix the track. The lightest diesel commonly around was 44 toner on 4 axles, or 22,000# axle load presuming it was ballanced end to end. Typical 1950 switch engine, or F unit, or Geep ran about 260,000 pounds or 65,000# axle loading. This was heavy enough to give good pulling power at low speeds, and any reasonably well maintained track structure of the era could support them.
Not all railroads had reasonably well maintained track structure, particularly on low traffic branch lines. For example, SP used GE 70 tonners on log hauling branch lines in Oregon; 140,000# on 4 axles is 35,000 pound axle loading.
The MILW had some "light" SD7 or 9 units. Typical SD was 390,000# on six axles, or 65,000# axle loading. This weight was achieved by "ballasting" the unit with concrete. If EMD left the concrete out could probably be as light as 280,000#, or 46,600# axle loading. Either CN or CP had some EMD switchers on six axle trucks for prairie grain lines. If they were 260,000# that gives 43,333# axle loading. I do not have weights for these last two, so this is illusrative, not definitive.
Mac
samfp1943 I know that the Commuter operations around Chicago were handled by a number of different railroads ( read also as different operating philosophies, as well) There does not seem to be much information on line as to those Chicago commuter lines. There were several, IIRC,: The ICRR, The Rock Island, The C&NW. I think that there were some on the C&WI, and of course the 'South Shore'. ( Maybe some of the Chicago area posters can add to, or correct my list.) Thanks!
I know that the Commuter operations around Chicago were handled by a number of different railroads ( read also as different operating philosophies, as well) There does not seem to be much information on line as to those Chicago commuter lines. There were several, IIRC,: The ICRR, The Rock Island, The C&NW. I think that there were some on the C&WI, and of course the 'South Shore'.
( Maybe some of the Chicago area posters can add to, or correct my list.)
Thanks!
Chicago suburban operations:
C&NW: Three lines (to Kenosha, Geneva and Harvard, with a branch to Lake Geneva)
MILW: Two lines (to Elgin and Walworth WI, later cut back to Fox Lake)
CB&Q: One line (to Aurora)
Alton: One roundtrip daily to Joliet
Wabash: One roundtrip daily to Orland Park
Rock Island: Mainline to Joliet and a suburban branch to Blue Island
IC: Electrified main line to Richton Park with branches to South Chicago and Blue Island
PRR: Two roundtrips daily to Valparaiso
South Shore: One line to Gary, Michigan City and South Bend
CWI: Two roundtrips daily to Dolton, discontinued in 1964.
Also, with regard to the diesels, my recollection is that in '54/'55 there were E or F units in use, at least during the commute times. I was to young to know the difference, but that general profile is stuck in my mind. I also remember being fascinated by the Mars lights.
CSSHEGEWISCH "Light" tends to refer to the size of the trailing tonnage, rather than the rail.
"Light" tends to refer to the size of the trailing tonnage, rather than the rail.
Just sign me as curious, and just wonderin' too!
Were any of the Chicago rail commuter passenger operations utilizing side tank engines, with bunkers in their commuter trains?
I am pretty sure that the NYC in their Eastern commuter operations; had fleets of saddle tank steamers, as did the Central of New Jersey. [ CNJ also used their 'Camelbacks', with tenders in their commuter ops as well. ] Not sure if the PRR had any for their Eastern Commuter fleets. (?)
My point is there does not seem to be a lot of information on Various Commuter Operations on the "NET".
The first HEP cars were the intercity bi-levels and re-built conventional cars for the 1958 "Flambeau 400" and "Peninsula 400". HEP for suburban service came shortly after that with the massive upgrade to air-conditioned bi-level gallery coaches.
The C&NW diesels that were assigned to commuter service in the 1950s included GP7s (with train lighting bulges on the end of the long hood), SD9s and H-16-66 baby trainmasters. There were also some "hammerhead" units (RS3's or RSD5s with high short hoods for the steam generators) that wandered into and out of the pool. All of those used steam generators to heat the cars, including the 1955 bilevels. When the first HEP cars arrived around 1960 a bunch of F7s from the freight pool were equipped with Cummins HEP power plants for train light and heat. The E-units were equipped with HEP as they moved to the commuter pool from the long-distance pool. Some E8s were also picked up as other RRs dropped passenger service. The last two E7s kept their steam generators for the Kate Shelley 400.
My recollection from the 60s is that the short 3-4 car midday trains drew the Fs, with the Es showing up on the 7-8 car rush hour trains.
Thanks. That was very helpful.
I found a few web sites talking about the Class E Pacifics on C&NW. It appears that the majority of those engines were the "light" models. Do you know if the track demanded a light unit, or is this just the way things worked out? Maybe cheaper to operate than the heavies?
Starting in the very early 20th Century, the Pacific class 4-6-2 became the mainstay for passenger service across the continent. Didn't matter if it was the high-speed 'limited' inter-city runs or commuter traffic at end-of-day, the 4-6-2's did the job well until the doubled and trebled volumes during WW II. Starting in 1939 and beyond, the Class One roads found they had to either double-head the 4-6-2 locomotives to get the required tonnages underway, or they had to resort to the newer and more powerful Mountain Class 4-8-2's with their Berkshire-equivalent boiler temps, pressures, piston cross-section, and appliances that offered much more efficiency per BTU. Whereas the Berks had drivers in the 69-70" range, the Northern 4-8-4's that were coming on line had drivers in the 72-80" range and could run like deer after they got their limited trailing tonnages lifted. So, the second world war saw increasing use of Northerns, Mountain Class, and even Challengers, Alleghenies, and the Duplex engines put into service by the Pennsylvania Railroad.
Crandell
Passenger steam locomotives on C&NW were generally Class E Pacifics in all services.
Does anyone know what make / type of steam locomotives were in use by the Chicago & Northwestern in their commuter service around 1954 / 55? I was a kid in Arlington Heights at the time and we used to go to the station to pick up my dad when he came home from work. All I recall is that there was a mix of diesels and steam and that I liked the steamers, but that's about it.
Thanks.
Our community is FREE to join. To participate you must either login or register for an account.