I’m curious as to how many streamlined passenger cars a 4-6-2 pacific would pull on, say, a 0.25% grade? also, how many freight cars? (yes, I know its a passenger engine)
Thanks
This is not a question with an easy, plug-in answer. It depends on the
size and design of the Pacific. For example, the GN had several classes
of 4-6-2s. Most had 73-inch drivers and were capable of good speed and
still be rated at around 35,000 to 45,000 lbs of tractive effort-depending
on the specific class. One class, however, the H-6, was a rebuild of some
older 2-6-2s. These had 69-inch drivers and had much better starting ability,
so they were often used as medium-duty dual service engines. ATSF, to give
another example, had large Pacifics with 80-inch drivers. These will pull
passenger trains quite fast, but have a harder time starting a heavy train.
In a nutshell, though, I would probably figure on a 6-8 car passenger train
or about 25-30 freight cars-again depending on the size and design.
Hope this is of some assistance.
20 freight cars is about what I figured. I know the A&WP 4-6-2 #290 has pulled 10 passenger cars relativly easy. It’s a Lima that’s been upgraded so it has a tractive effort of like 40-50,000 pounds.
It all depends on so many factors, such as the size of the drivers, firebox (bigger being better) and weight on drivers. Remember, steam engines were built for a specific “job” or assignment, there were very powerful Pacifics built, such as the Erie’s USRA heavy Pacifics, which had to move a 1000 ton train on a sawtooth profiled railroad. The grades topped out around 1.5-2%, and they did not get helpers on most trains they ran on. Speed wise, they were good up to 65-70 MPH. PRR’s K5 duet were big as all outdoors, but with 80" drivers without enough weight on them and being hand fired (at first,anyway) hamstrung them. New Haven’s I4 class was a very sound design, and properly used. The NH got nearly three decades of mainline service out of them. They handled 1000 ton trains at up to 70 MPH without straining. Pacifics were in my mind, with the exceptions noted, generally purpose built. Some were built more for economy than sheer power (CP, NKP,NYC,Lehigh Valley). While others were crafted for a specific task(NYCs class K11,andK14 stand out as local/commuter power, as were CPs G5 class, which have a surprising number still in existence! Running, yet![;)])
I should’ve mention that the CGW Baldwin Class K-5 is what I’m interested in. when I made the original post I forgot how many different classes of Pacifics there are.
The Pacific locomotive spanned a large performance range from small branch line locomotives to ones that were quite powerful. One of the most powerful Pacifics was the B&O class P7 (53,000 lbs TE and 80" drivers) that produced 4-6-4 Hudson like performance.
www.northeast.railfan.net/images/bo5301sa.jpg
Cool.
Pennsy owned a K5 build by Baldwin (#5699) that produced 54,675 lbf of tractive effort which is quite amazing for a Pacific, and beat the K4s by about 10,00 lbf. However, the factor of adhesion for these super-Pacifics was quite poor, resulting in their general failure as heavy road passenger locomotives. Consequently, Mountains and Northerns (cough Niagras) were used instead.
Cheers!
~METRO
As with all Steamers, you’ll need a specific version for a specific line to answer this question.
And pacifics weren’t “Passenger engines” at all, that’s just what they were usually doing.
I can’t speak for the Pennsy K5, but the B&O P7’s actually had more adhesive weight on their drivers than Hudsons. (This was the main reason why the B&O generally did not like 4 wheel trailing trucks–it took adhesive weight off the drivers) The B&O did use them in heavy passenger service in mountainous terrain for many years. The P7’s factor of adhesion of 3.8 is actually better than the N&W J 4-8-4.
The N&W J Class had that low adhesion? [sigh] You know, I gotta say the more I learn about the J Class the less I think of them, so much for childhood heros.
Anyways, the factor of adhesion of Pennsy’s K5 was also 3.8, which you’re right isn’t horrible. However the compairable K4s-class had a factor of 4.54 which is none too shabby.
Also, because of electrification the Pennsylvania had a surplus of K4 types and mountains it was easier to just use existing designs instead of pouring more resources into developing a new class. The K5 was eventually assigned to the Pittsburg-Crestline route after being found unsutible for Harrisburg-Baltimore runs.
Theoretically, these engines should have been perfectly good passenger haulers, if only Pennsylvania was flatter.
Also to answer the original question, after a bit of searching, the Chicago Great Western 1913 Baldwin Built K5-class locomotives had a tractive effort of 40,800 lbf. They were the largest Pacifics owned by CGW and beat
The N&W J’s had a low factor of adhesion of 3.6 due to their high boiler pressure, small drivers, and limited adhesive weight (only 4 driving axles). Not the best combo for pulling a heavy train at low speeds, but once the J got a train moving, it had a pretty good HP punch up to 40-50 MPH.
Metro,
Needn’t give up childhood heroes. The J’s were not designed or used by N&W to pull up stumps at 0-10 mph. There were plenty of Y6’s around for that job. Those large cylinders were used to keep speeds up on heavy grades and ,as noted by GP40-2, to have a significant punch at medium operating speeds. This helped them recover time from 25 mph curve restrictions.
Understand that it doesn’t take 80,000 lbs TE to start a 15 car train all the time (about the maximum N&W expected one J to handle over the railroad). A J could start this kind of load at part throttle if rail conditions were not ideal. However, if all the cards were right, you better hold on. In excursion days, 611 could get a 18-20 car train underway pretty fast.
GP40-2,
I’m glad you brought up the B&O P7’s. They’ve always looked like the “sleeper” among 4-6-2’s. I don’t think many people have considered their capabities. Although their basic specs were very close to “that other railroad’s” K4, the increased boiler pressure (230-250 psi??) put them in a different class.
Thanks for the info.
The 611 pulled 25 passenger cars in the early 1990s with no trouble. It’s on a Pentrex tape. Also, remember J’s were designed to run at speeds of about 100 MPH.