ps4 Pacific in freight service

[UP5521]

I just recieved the southern 4-6-2 pacific from VMD which I numbered 1401 which is running on the fictional Tidewater Western Railroad[under construction] and I was just curious on how many freight cars and the horsepower rating despite this engine is really a passenger engine can haul,I'm just don't want to hold up alot of people at the grade crossing which has happened before but,with a different steam engine and I want the train length to look like the prototype freight trains of today I am scaried that the grades could become a problem,if someone has any ideas on how to resolve this,thanks!

 

[on30gn15]

Whether this is actually any kind of answer to the question being asked is open to interpretation, but here go some comments.

Are the factors being asked of the world solely within TRAINZ or of the 3D world too?

"How many cars" is going to vary, and dramatically so, depending on the weight of those cars - and the grades involved.

And the weather - gotta have adhesion to get the tractive effort to haul the tonnage; horsepower only gets you speed.
Wet rail means less adhesion.
And lots of sanding.

Back in the steam days, bitter cold would also substantially lessen the number of cars on account of, ah, forget what, but do remember reading that several different places over the years.

Example of the grade issue is that somewhere in a book on the MILW's electrified lines observation is made that at one location where it ran close to NP, on the NP some articulateds classed Z-something, I think, were only rated 600 tons on that particular grade.
In terms of modern 100 ton grain hoppers - that's six cars.

SOU's Saluda would do kind of the same thing.

Also going to depend on what kind of acceleration and deceleration behavior will be required - in a paraphrase of an old math formula, when it comes to starting and stopping trains, "weight = time & distance"

 

[on30gn15]

Here ya go, some guidelines in here: http://www.steamlocomotive.com/pacific/

"ALCO's 50,000, which, as many readers are aware, had a long and successful career after its service as a demonstration locomotive as Erie 2509. It was one of, if not the first, example, of the "heavy" Pacific, designed and built to handle the passenger trains which were approaching 800/900 tons behind the tender, "

One of the most interesting developments was on the ACL. This company ordered 165 further Pacifics, identical to the USRA ones, except that they had 69-inch drivers and 210 lbs boiler pressure. These Pacifics, with a starting tractive effort of 45,275 lbs. On the relatively flat route between Richmond and Savannah, these Pacifics had a freight tonnage rating of 4400 tons (unadjusted) in either direction. And, with their 69 inch drivers. they were more than capable of maintaining the moderate passenger train schedules of the 1920s and early 1930s. 5

Given the Southern PS-4 Pacifics' ratings of 72in drivers and 47,500lbs tractive effort, probably be pretty safe to expect same tonnage on the flat.

(for whatever reason, larger drivers seemed to have lower tractive effort - seems large drivers = higher speed, lower TE; small drivers = lower speed, higher TE; don't know the physics, just that that's been read consistently time and time again over the decades)

If you're talking 100 ton cars, 44 cars; 80 ton cars gets 55 cars.

Be safe, likely, to cut that by 10 cars for every 1% increment of grade to be encountered.

 

[UP5521]

it is almost no wonder why these steam engines are different from the others in terms of power,speed,fuel,water and other steam engine specifications,if I run the 1401 from lets say,from Richmond VA to chicago illinois,with a loaded freight train,does the numbers stay the same or does it change,because I want to try to eliminate adding a helper engine district on the railroad,just like the prototype railroads did,I was watching a video that featured the massive 4000'class 4-8-8-4 big boys that was claimed to be the largest steam engines ever built and was seen climbing the grades in the west,I wonder how that differs from the PS-4 engine's rating,and these were designed for freight service!

 

[on30gn15]

Okay, just found the Milwaukee book mentioned above.
"At Henderson, 18 miles west of St Regis," in Montana.

NP loco is a Z-3 compound 2-8-8-2

"Don't be misled by the length of train behind the mallet. 600 tons is about as much as this engine will be able to handle beyond Hagan, when it encounters the NP's own 4 percent grade over the Bitteroots to Wallace, Idaho. This will be a spectacular show."

p.87 Under Milwaukee Wires, Bill Marvel, pub. Morning Sun Books 1996

That "length of train behind the mallet" is 5 cars.
Yep.
Five.
Including the caboose.

 

[UP5521]

that is alot of cars,with just one engine doing all of that,was there even a engine on the rear at all,because from the way it sounds,trying to get a 5 mile long train up the grade is a tough task!

 

[on30gn15]

Comparing Big Boy 4-8-8-4 locos with Southern Ps-4 4-6-2 locos is something like comparing 18-wheelers and Ford Woodys.

Other than being steam locomotives there's not much in common between the two.
Ps-4 was designed to pull medium sized passenger trains over rolling land into Appalachian foothills.
Big Boy was designed to move large freight trains across open western landscape with the minor interruption of Sherman Hill being taken into account.

As well as the size, there's a 20-year difference in technology with the Ps-4 being built from a 1920s design and Big Boy being a 1940 design

Okay, here we go, found some more info.
It is said the Ps-4 could given level ground, get 14 passenger cars up to 80mph.

Big Boy "developed a pull of 135,375 pounds"
That's a wee bit different from the Ps-4's 47,500
In ballpark figures one could expect Big Boy to easily haul 3 times what the Ps-4 would.

Comment is made that UP enginemen had said Big boys would do up to 80mph in the right conditions but developed their best power around 30mph.

Above comes from, pp. 154, 260; Steam Locomotive Cyclopedia, pub, Kalmbach Books c. 1960

and it's a pretty fair bet that 80mph in a Big Boy sure ain't gonna happen with 200 boxcars uphill on a 3 percent grade.

 

[UP5521]

ah,now I see,so since the numbers are different,it indicates that the big boy was built for heavy trains,that means that this particular engine is designed for medium sized trains,now I know what I'm dealing with,and as for the gradient,I'm going to keep it to a minimum,thanks!

 

[on30gn15]

You're welcome.

Hmmm . . . wonder what a Big Boy would look like in Sylvan green . . . .

 

[UP5521]

a big boy in green,no,I don't think the Union pacific would not be happy to see that!:hehe:

 

[on30gn15]

How UP feels about it is not my problem :hehe:

 

[Gandalf0444]

It can't possibly look that bad in green:wave: