The Pennsylvania Railroad K4 Tractive Effort (Power), Or Lack Of.

[HD SIMULATIONS]

In the real world the PRR K4 Develops Tractive effort 44,460 lbf (197.8 kN). In the game it cant budge 7 P70 Passenger cars. By comparison, Baldwin Sharknose's Develop Tractive effort 43,000 lbf (191.3 kN). Thats right folks, K4 Steam locomotives should have more power then a Baldwin RF-16. Yet in the simulation the Baldwin RF-16, develops way more tractive effort then the K4. Why not set the K4 up properly? It was the backbone of the PRR. I hate the fact that all steam locomotives with few exceptions lack any pulling power. I love old steam Locomotives, American, English, Scottish, Chinese, all kinds. But in this game the power ratio between them and diesels is unexceptable. Please address this issue. I bought the K4, knowing it develops more power in real life then most early diesels. Yet in the simulation it is the most underpowered piece of crap in my entire roster. When developing Steam locomotives for the simulation, One should start power development by studying the Tractive Effort of the said locomotive, as this is how power is measured on locomotives, not horsepower. Horsepower = How fast a diesel engine can accelerate RPM, RPM = Crankshaft Revolutions Per Minute. Torque on Diesels = how much power is transferred from the crankshaft to the generator per RPM. Tractive Effort = How much force a locomotive is able to exhibit to the coupler. Therefore, tractive effort is the most critical aspect of a locomotives power. Torque really isn't a factor, as it would be in a tractor trailer or a car, due to the fact that in a locomotive the power from the Crankshaft is transfered through the generator to electrical power into the traction motors, that then produce the TRACTIVE EFFORT. That is why all locomotive power is measured by tractive effort. Both Steam and Diesel power can be accuratly measured through tractive effort, as both horsepower and torque are transferred.

[Smokebox]

Partially right. In a steam locomotive, boiler horsepower is very important, because it's a factor that limits how fast the locomotive can go before the steamusage outstrips the capacity of the boiler to produce steam.

[HD SIMULATIONS]

Totally right, All of your locomotives are underpowered. Most of them are under parametered. I've never seen The 765 struggle with 20 cars in reality. Or the FEF-3 struggle with any train its ever pulled. The reality is that tractive effort pulls the train. Boiler pressure pushes the cylinders in relationship to the size & bore. Steam energy is then transferred to mechanical energy, thus being measured by TRACTIVE EFFORT. Go to youtube and watch some long steam drags.

[HD SIMULATIONS]

Nickel Plate 765 - Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Nickel_Plate_765
Wikipedia
Tractive effort, 64,135 lbf (285.3 kN)





EMD GP9
Tractive effort 64,750 lbf (288.0 kN)



When early diesels first came out, engine crews didnt want them because they wouldnt pull a hill as well as their old steam locomotives. There isnt a single Steam locomotive in this game that will pull a sustained run = to a GP9. In reality a Berkshire would have ran away from it with an equal weight train. They did 70-75, usually much faster then that. Geeps did 65. Im still a huge fan of your work Smokebox. They just need more power.



https://en.wikipedia.org/wiki/Tractive_force


Steam locomotives[edit]
An estimate for the tractive effort of a single cylinder steam locomotive can be obtained from the cylinder pressure, cylinder area, stroke of the piston[note 2] and the diameter of the wheel. The torque developed by the linear motion of the piston depends on the angle that the driving rod makes with the tangent of the radius on the driving wheel.[note 3] For a more useful value an average value over the rotation of the wheel is used. The driving force is the torque divided by the wheel radius.

As an approximation, the following formula can be used (for a two-cylinder locomotive):[note 4]

t = \frac {cPd^2s} {D}
where

t is tractive effort
c is a constant representing losses in pressure and friction; normally 0.85 is used[note 5]
P is the boiler pressure[note 6]
d is the piston diameter (bore)
s is the piston stroke
D is the driving wheel diameter


The constant 0.85 was the Association of American Railroads (AAR) standard for such calculations, and overestimated the efficiency of some locomotives and underestimated that of others. Modern locomotives with roller bearings were probably underestimated.

[HD SIMULATIONS]

Values and comparisons for steam locomotives[edit]
Tractive effort is the figure often quoted when comparing the powers of steam locomotives, but is misleading because tractive effort shows the ability to start a train, not the ability to haul it. Possibly the highest tractive effort ever claimed was for the Virginian Railway's 2-8-8-8-4 Triplex locomotive, which in simple expansion mode had a calculated starting T.E. of 199,560 lbf (887.7 kN) — but the boiler could not produce enough steam to haul at speeds over 5 mph (8 km/h).

Of more successful steam locomotives, those with the highest rated starting tractive effort were the Virginian Railway AE-class 2-10-10-2s, at 176,000 lbf (783 kN) in simple-expansion mode (or 162,200 lb if calculated by the usual formula). The Union Pacific Big Boys had a starting T.E. of 135,375 lbf (602 kN); the Norfolk & Western's Y5, Y6, Y6a, and Y6b class 2-8-8-2s had a starting T.E. of 152,206 lbf (677 kN) in simple expansion mode (later modified to 170,000 lbf (756 kN), claim some enthusiasts); and the Pennsylvania Railroad's freight Duplex Q2 attained 114,860 lbf (510.9 kN, including booster) — the highest for a rigid framed locomotive. Later two-cylinder passenger locomotives were generally 40,000 to 80,000 lbf (170 to 350 kN) of T.E.

https://en.wikipedia.org/wiki/PRR_Q2


The Pennsylvania Railroad's class Q2 comprised one prototype and twenty-five production duplex steam locomotives of 4-4-6-4 wheel arrangement.[1][2][3]

They were the largest non-articulated locomotives ever built and the most powerful locomotives ever static tested, producing 7,987 cylinder horsepower (5,956 kW) on the PRR's static test plant. They were by far the most successful duplex type. The duplex propensity to slip was combated by an automatic slip control mechanism that reduced power to the slipping unit.

The Q2 locomotive was 78% more powerful than the locomotives that PRR had in service at the time, and the company claimed the Q2 could pull 125 freight cars at a speed of 50 mph (80 km/h). [4]

Despite overall success, the Q2s were all out of service by 1951. With dieselization, they were the obvious first targets to be withdrawn since they were only a little more capable than the conventional J1 class 2-10-4s but with far higher operating and maintenance costs.



Maintenance costs killed the Steam Locomotive, Not the lack of power.



DD40X
Tractive Effort (starting) 113,940 lbs @25% Tractive Effort (continuous): 103,000 lbs @ 12 mph.

DD40X Would be equal to a PRR Q2. Or C&O 2-6-6-6 also known as Allegheny's, Gene Huddleston's book, "C&O Power", reports tests of the C&O with a dynamometer car indicating momentary readings of 7,498 hp (5.6 MW) with readings between 6,700 to 6,900 hp (5.0 to 5.1 MW) at about 45 mph (72 km/h). The state of calibration of the dynamometer car is not known. The calculated starting tractive effort was 110,200 lbf (490.2 kN).


UP 3rd Generation GTEL's Hold The Record.
8,500 HP. Tractive effort 212,312 lbf (944,410 N) 3rd Generation.

[HD SIMULATIONS]

Make us some TRACTIVE EFFORT, :) I've often wondered how much power an Allegheny, or a Big Boy could produce if the coal and firebox was replaced with a nuclear reactor-steam generator. That would be some serious sustained Tractive Effort. The crews would just have to make sure they were full of water. The fuel would have a half life of 500,000 Years lol. Although it would be totally dangerous.

[customhitcher1]

thanks for the return to collage class. way to much info,yet cool to read and learn. A nuke? now that be cool! the water would be an issue unlike the navy.

[HD SIMULATIONS]

Copy that Custom Hitcher... Thats why they should be outlawed before anybody builds one. lol. I can also make a 460 Cummins Diesel make 1,000 HP. but thats a lesson for another day.