Tractive Effort - What Could an SW7 *really* do?

[norfolksouthern37]

must be N scale...

 

[frogpipe]

:hehe: ........

 

[Azervich]

must be N scale...

when I was 16 I asked a guy who run a hobby shop 'how much would 100 tons be in HO scale' then he got the calculator and answered 87kg, that was back in 2001 and I haven't forgotten since, I wonder what N scale would be if it was scaled. lol

 

[kws4000]

when I was 16 I asked a guy who run a hobby shop 'how much would 100 tons be in HO scale' then he got the calculator and answered 87kg, that was back in 2001 and I haven't forgotten since, I wonder what N scale would be if it was scaled. lol

No, not really. Mass is 3 dimensional, so it is not just multiplying/dividing once as with length, you have to do it three times. EX: 100T*2000lbs=200,000lbs. [(200,000/87)/87]/87=.303 pounds in HO scale. N scale, for 100 US tons, = .115 pounds. And with 4.8 oz in HO scale, that is probably pretty close to the NMRA standards for car weights (which is actually based on length).

 

[frogpipe]

I'm not doubting you, but I would really like to see the science behind this - could you point me to it, or give me a clue what to search for on the net? I presume it's some part of physics.

 

[matruck]

So after all this mathematics what can a SW1200 really do ? Please.
Mick.

 

[Azervich]

Hi Mick,

It has 36,000lbs continuous, so I'd rate it close to our C Class 2-8-0 '205%' which is 38,400lbs at 85% MEP WP, so for a 1in48 '270 tons' so you'll go 205/270tons = 553tons.

EDIT:

Keep in mind though that Diesel Locomotives have better adhesion over steam locomotives, even though T.E is lower it's adhesion is higher, so I'd add 10~15% over a steam locomotive, I've recalculated, SW7 and SW1200 are the same, seems to be different naming, so the SW7 should also be rated just above 205%, but the other thing is gear ratio, lower gear ratio gives more power so it's a higher percentage, taller gear ratio is a lower percentage, the problem is trainz doesn't model gear ratios, so you can't tell trainz how much acceleration the loco should have as it's based on T.E's.

Cheers.

 

[matruck]

Thanks Aaron i'll be back with more questions once i work out what all that means when trying to put it all in Trainz mate..LOL. Thanks mate.
Cheers Mick.

 

[Azervich]

Hi Mick,

Maybe this will help, it's a full scan of one of the books I have.

http://tinyurl.com/LoadsOfGoodsTrains1926

Cheers.

 

[matruck]

Thanks heaps Aaron.
Cheers Mick.

 

[Pendolino]

but the other thing is gear ratio, lower gear ratio gives more power so it's a higher percentage, taller gear ratio is a lower percentage, the problem is trainz doesn't model gear ratios, so you can't tell trainz how much acceleration the loco should have as it's based on T.E's.

Trainz does not model gear ratios, but you can implement them in the enginespec config, but this requires some extra research

Let's suppose you have two different locomotives, one geared for passenger trains (max speed = 100 MPH), one for freight trains (max speed = 50 MPH).

If you know the different gear ratios, that's fine; otherwise you can assume that electric traction motors, at max. loco speed, are rotating to their max. rpm rating. The ratio between the TE of the two locomotives will then be equal to the ratio (reversed) between their max speed.

If the passenger version has a TE equal to 100.000 lbs at 40 MPH, the freight version, at the same speed, should have a TE equal to 200,000 lbs (obviously, its traction motors will be rotating at double speed).

It's like using the same boiler for a low-drivered Consolidation or a high-speed Pacific .