Was watching NYC Steam in Ohio from Herron Video on RFD-TV that other day and they said the NYC had purchased some Mohawks that could be used in both passenger and freight service. I realize that diesels need a steam generator to be used in passenger service but what made a steam locomotive passenger ready?
Thanks
Chris
Not much. Steam lines to run the heat in the cars was about all that was needed. Many cars generated their own power from axle-driven generators on the trucks.
-Crandell
The L4 class of Mohawks were considered dual-service locomotives, they had 72" drivers versus 69" on the earlier classes. This gave them a little higher top speed, without compromising too much power, and made them suitable for second tier passenger duties.
Some steam locomotives in suburban service were also equipped with lighting generators to provide power for train lighting.
Thanks all for the info…
Passenger steam engines were also equipped with a train signal line. A second air line that worked with the train signal cord that ran down the roof of all passenger cars. If you pulled on that cord it didn’t affect the airbrakes but still signaled in the cab.
Useful CP spotting feature: Passenger equipped engines had the large outlined panel’s on the side of the tender painted Tuscan Red to match the coaches. Freight engines had the panel outline but was left black behind the words Canadian Pacific.
AgentKid
Also something about brake airline pressusre. I recall reading somewhere that freight trains required 85 psi, passenger trains 110 psi and “dual service” locomotives had to be “convertable”.
The automatic brake had an adjustable feedvalve, so the engineer set the pressure at whatever was required.
Is there some type of device to reduce the steam pressure to saturated steam for use by the coaches? What is this device called? Is this device not present on freight steam locomotives?
You’ve been waiting quite a while for an answer so I will put my in my 2 cents worth[2c]. I think the absence of a steam heating line running under the tender from the boiler of freight loco renders the need for whatever the device is called moot. I think you are right about the saturated steam part though. My father had many stories about freeze offs in the lines at the coupling points between coaches in Saskatchewan at -30 degrees F, in the diesel era. If it wasn’t saturated steam there would be no water to freeze off, would there? I hope this helps.
AgentKid
I’m pretty sure that the train heat steam line was fed through a pressure reducing valve. Running it at full boiler pressure (up to 20 kg/cm2) doesn’t seem like it would be the swiftest maneuver.
That line most likely took steam from the turret, on top of the boiler just ahead of the cab, so it would have been saturated steam, not superheated.
The most obvious spotting feature for steam locos intended for passenger (or dual service passenger/freight) service would be the train heat and train signal connections. Pure freight locos wouldn’t have them. OTOH, some rather unlikely locomotives did have them - N&W’s A class 2-6-6-4s, and a lot of 0-8-0s used for switching in passenger terminals are obvious examples.
The biggest feature that separated steam designed primarily for passenger service was tall drivers - up to 86 inches (NYC999 as built.) Not until the latter days of steam did anyone worry much about moving freights fast, so pure freight locos were built with drivers that averaged about 63" diameter and topped out at 69" diameter.
Chuck
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This is not a reliable method of determining whether CP steam locomotives were passenger equipped.
Point in case: the G5 Pacifics, (the backbone of CP’s passenger motive power) not one of them had tuscan tenders. None of the P1s and only a small handful of P2s had tuscan tenders and they were all designated as dual service locomotives.
However, running freight trains at passenger train speed is not new for intermodal. The Atlatnic Coast Line and connecting RF&P would handle long iced regrigerator car trains of Florida and Georgia fruit behind Pacifics before the dual-service Northerns were put into service. The Noirthern Pacific silk trains are another example.
To add a little to this:
My study/experiance is mostly with North East/Mid Atlantic roads (B&O, C&O, NYC, PRR, etc). It was common on these roads for almost everything to be passenger capable. Those N&W class A’s pulled lots of passenger trains in their day. The B&O used their 2-8-2’s to fill in for Pacifics on locals in rural Appalachia all the time, and the Mikes where often the passenger helper of choice on grades.
The B&O even tried using their 2-8-8-4 (EM1) on long heavy passenger trains over the mountains, until they put one SERIOUSLY on the ground by going a little too fast. Even so those locos all had steam and signal lines.
North East/Mid Atlantic steam railroading differed from most of the rest of the continent in a few ways. Partly because of geography, and partly because its where North American railroading started, grades are steep, curves are sharp, and distances between cities are small. So speed, even for passenger service was less important than it was in covering the vast open range of the west. Even the Rockies allowed longer smoother grades and broader curves than many of the routes over the Appalachians.
So even the most modern East Coast steam generally used smaller drivers or had less of them than their West Coast/Mid West counterparts. Examples: SP GS4 - 80" drivers, N&W Class J - 70" drivers and the C&O H8 2-6-6-6 weighed more than the UP 4-8-8-4 Big Boy, but needed the shorter wheelbase of each driver set for east coast curves.
IIRC, even those C&O Alleghenys did their fair share of passenger service from time to time.
Sharp vertical and horizontal curves in the east limited the use of long rigid wheel base steam locos. There where some, but where they where used was limited. The B&O built it super sized 2-10-2’s for its Sand Patch grade (a long, steady, climb with broad curves) but put
So even the most modern East Coast steam generally used smaller drivers or had less of them than their West Coast/Mid West counterparts. Examples: SP GS4 - 80" drivers, N&W Class J - 70" drivers and the C&O H8 2-6-6-6 weighed more than the UP 4-8-8-4 Big Boy, but needed the shorter wheelbase of each driver set for east coast curves.
What?
East Coast 4-8-4: NYC S1-b: 79" drivers, ACL R-1: 80" drivers
East Coast 4-6-2, Pennsy K-4: 80" drivers, NYC K-3/K-5: 79" drivers, B&M P4: 80" drivers, B&O P-7: 80" drivers, Erie K-5: 79" drivers
Midwest/Western 4-8-4: Cotton Belt L-1: 70", TP&W H-10: 69", GN S-1: 73", SP classes GS-1, 2, 3, & 6: 73" (there were more of those than GS-4/5), D&RGW M-64: 70" (M-68’s had 73").
Pacifics: GN H-x 4-6-2’s all had 73" drivers, SP’s heavy Pacifics had 73" drivers. Santa Fe’s were built with 73", but most were rebuilt with 79" drivers (although I think the rebuilds stayed east of the Rockies), T&P 4-6-2’s had 73" drivers as did MP’s, Rock Island’s, etc.
Edit: Oops, I misspoke. SP’s GS-3’s were also 80" driver engines, so the preponderance of SP 4-8-4-s had 80" drivers.
You just can’t just generalize.
As for grades and curves, it would appear you’ve never been around Tehachapi or the climb up Cuesta, not to mention the Siskiyou Mountains. Climbing the Front Range of the Rockies out of Denver presents some pretty tight curves. Donner Pass is pretty curvy too.
Andre
Andre,
Yes there where lots of exceptions, but most of the East Coast locos you listed with drivers in the 80" range had only three coupled axles, keeping their rigid wheelbase short. The few others you listed where used on water level routes with mild grades and broad curves.
I don’t think you would disagree that steam locomotives where designed and used based on the requirements of the line. Those requirements did not simply seperate “large” drivered locos as passenger and small “drivered” locos as freight. AND, as the most modern types developed, there is a very obvious move to larger drivers in the west and smaller (call them medium sized) drivers (or less of them) in the east and to dual service usage.
The Big Boy vs Allegheny/N&W Class A comparison is a valid one. Both eastern locos have similar weight and power as the Big Boy, yet both where built with higher axle loadings and shorter rigid wheelbases to meet the curves and conditions of the lines they ran on. Big Boys would have been useless on the C&O or the N&W and would have had trouble with a much larger percentage of the available trackage (curves) in the east. Are there tight curves and sharp grades in the west, to be sure, but as a precentage very little of the trackage out west was as curve/grade restricted as the east. If these factors where not true, than the N&W should have built the “J Class” with 80"+ drivers like the GS4. instead they used a a 70" driver, smaller than ANY GS class loco on the SP and with a correspondingly smaller rigid wheel base, for sharper curves.
Yes these are two exceptions, exceptions that never really got anywhere near an east coast mountain pass.
I did not mean to “over generalize” and in earlier des
Andre,
Maybe this will make my point more clear, using the Big Boy vs 2-6-6-6/2-6-6-4 example.
The UP had the “option” to straighten out some trackage for the Big Boy if need be, but in the east the geography, cost of construction and available real estate made heavier rail/roadbed and the shorter rigid wheel base of only three coupled axles axles a better choice. A choice reflected by lots of other design choices in the later years of steam.
The B&O never owned a Northern and never owned anything with four coupled axles and 79-80" drivers. Too many of their curves would not allow it. Their unique 2-10-2’s failed on other parts of the line as explained. Loco choices on other lines where similar. The PRR and NYC had easier routes over the mountains and some longer locos than the B&O, C&O, N&W or WM, and still never used anything like a Big Boy or a 2-12-2.
Again, I konw this is complex with lots of specific exceptions, but a clear pattern does exist in the development of the more modern designs.
Sheldon
The OP was interested in passenger vs freight useage, my examples show the use of many “freight” types in passenger service in the east, and thereby explaining why east coast roads had many freight types with steam heat and signal equipment.
As for exceptions, many roads in the “flatlands” of the southeast (like the ACL) used “passenger” types, like Pacifics and Mountains, for large percentages of their freight service. But of course the Mountain type was truely the first large dual service loco. The B&O and the C&O saw them as passenger power, but the the NYC and many southeast roads used them extensively for both.
I admit the design and application of steam locos to there tasks is complex, I simply tried to explain one “part” of it for the OP’s question.
Sheldon
Well, you may know about the East, but you don’t know much about the west.
The 63" driver Harriman Mikes for both SP and UP were originally assigned to passenger trains.
SP’s cab-forwards, nominally a freight locomotive, were used on passenger trains over Tehachapi and Donner.
Early on, SP’s 4-10-2’s saw use on passenger trains.
SP’s roster of both 4-8-2’s and 4-8-4’s were considered dual service engines and were used on both freight and passenger trains.
SP also used Pacifics for freights and even rated its A-3 4-4-2’s for freight service in the San Joaquin Valley.
UP’s Challengers were used with some frequency on passenger trains, especially in the Blue Mountains of Oregon.
With respect to B&O not having any 8 coupled passenger engines, I would guess the more likely explanation is that B&O trains never reached the 16-20+ car lengths reached by such trains as the Daylight, Overland Limited, etc.
I don’t think you would disagree that steam locomotives where designed and used based on the requirements of the line. Those requirements did not simply seperate “large” drivered locos as
Andre,
You have taken my meaning completely wrong in this. All of those western facts you stated I am at least somewhat familiar with, and/but I do admit to not having much detailed interest in railroading west of the Mississippi. You could offer the OP even more insite by explaining more about the practices of western roads and how common the universal appliance of passenger heat and signal lines where on those roads. I don’t know that answer. Never said I did. I answered that question in relation to the east and gave some other info about locomotive use and developement on eastern roads.
The B&O had eight coupled engines, just no Northerns. They had a large fleet of 4-8-2’s, largest driver size 74", most only 70". Why did they never buy/build a 4-8-4 with 80" drivers? (like GS4’s or FEF’s) or any eight coupled loco with 80" drivers? Because its rigid wheel base would have been a problem on at least 30-40% of their trackage. Such a loco could have run on their trackage, but not a the speeds it was designed for, so what use would it have been?
On the B&O, name trains where often only 8-15 cars or where run in multiple sections, but many other lesser class passenger/mail runs where often 15-20 cars. East coast name trains seldom carried the mail. That was left to the non discript, every hour on the hour type of trains, but those could easily be 15-20 cars long. Pulled by one 4-8-2 from Baltimore to Chicago except for a help over some grades.
I in no way implied western roads didn’t do these things or never used their various locos in these ways. I simply stated what I know about east coast roads using traditionally freight power for passenger service as the OP seemed surprised that a big articulated would be pulling a passenger train. Because I am not as versed in the details of western power, I did not assume beyond my knowledge abo