Realistic horse power

[Ghost42]

Have been swapping out my CP9s for the SD70M for more pulling power - just love the sound of the engines, the result was overheating engines and less power.
Digging deeper I studied this article:
https://en.wikipedia.org/wiki/San_Bernardino_train_disaster
which now shows me why I see consists with multiple locos.
I set up four tracks and consists, 4 miles long with a set gradient and load, first over the line was a SD80 just pipping a 44 ton shunter followed by a C30-7 and a long way back was the SD70.
I can dismiss the 44T as unrealistic but was the SD70M realistic and the rest also pulling above their weight?

 

[Ghost42]

Ok, using a speadsheet found online I inputted the data from my test results, using a C30 - 7, 1 in 50 gradient, 990 tons in 9 minutes 30 secs.
Result: 3100 hp.
Happy with that and shall use it to formulate consists.

 

[Azervich]

Hi Ghost,

Locomotives are not entirely based on horse power as rated in engine data sheets, the engine turns a generator or alternator, engine HP is used to help turn it under high resistance in the electro-magnetic field, the locomotive pulling power is amps x gear ratio x axle load x adhesion.

For example a locomotive of 2250 hp can have 212kn of traction on a 59-18 gear ratio with 6x D-52's and D-77's while another locomotive with 2250 hp can have 253kn of traction with a 71-18 gear ratio and 6x D-43's or a 2150 hp can have 311kn of traction with a 65-18 gear ratio and 6x AEI 165's.

So we have 3 locomotives with same engine hp but different pulling power, so to make trainz physics seem more realistic is to use the continuous traction on locomotive data sheets then put that in the notch 8 power then make a curve sheet from that using data that can be 25% adhesion to 40% adhesion on the crawling/starting speeds, the SD70M should have about 500kn of traction at about 20km/h.

is the 990 tons short tons or long tons or metric tonnes? I believe a C30-7 should pull 1600 tonnes on a 1in50 Grade.

Cheers.

 

[JCitron]

Have you tried the engine profiler in T:ANE?

Check out the Test Track, which you can get to from the Launcher or via Content Manager from the File menu.

 

[Ghost42]

I am no expert using the Test Track but the power output (1976kn) of the SD70 appears normal as does the power output of the C30-7, the figures at 20km/h also tie up.
On the Test Track the 70 well outperforms its opponent showing the difference in power..
As I understand the gearing would be suited to the job in hand, fast freight/passenger versus heavy haul.
I'll remember to add enough locos to maintain an optimal speed of 25mph with sufficient dynamic braking, the rest I'll leave to the experts

 

[JCitron]

I'm no expert either on this subject, but the SD70AC, though, is supposed to be for heavy-haul operations.

The railroads do run these in multiples, like 3 or 4 SD70s together and a couple on the end too as pushers, or as distributed power.

There's a spreadsheet available, from the guys at Jointed Rail. I think it's Justin Cornell who put it together, but I might be mistaken, which gives the number of locomotives required based on the tonnage.

 

[blueodessey]

Try this link.......

Thread: Looking for this Spreadsheet Engine HP rating

Thank you for the Spreadsheet

It works perfectly in the manner you described.......Much appreciated
===========================================

norfolksouthern37
Sweetwater, TN, USA

I made this years ago following some research I was doing. I have put it up so you and others can get it if they wish.

http://jrpcloud.com/files/public/files/HPcalc.xls

To use it just fill in the blue areas (at least I hope they are blue on the file). The yellow/orange areas are general calculations based on what you entered.


From <http://forums.auran.com/trainz/show...gine-HP-rating&p=1584624&posted=1#post1584624>

 

[Ghost42]

Thanks for the spreadsheet links.
Having revisited my test track and properly loaded the locos a more realistic output is obtained, the SD70 showing its true colours on the gradient, takes longer but does the task in hand.