Locomotive Drag Racer?

[RailroadDoc]

Okay -- here's the ultimate trivial question. . . and it comes from my love of trains and drag racing!

If it was possible to enter a locomotive in a quarter mile drag race -- what would it's quarter mile time be?

I'm assuming a locomotive that's not pulling anything.

I did some rudimentary calculations. I've got a mustang with a small engine that develops 220 hp; it weighs about 3400 pounds, and would turn the quartermile in maybe 15 seconds. The horsepower/tonage ratio (220/3400/2000) works out to about 130 hp/ton. A modern locomotive will weigh about 200 tons and have 4000 hp -- for a ratio of 20 hp/ton.

So -- it looks to me that the propulsive power ratio would be about six times as great for the mustang as the locomotive -- which suggests that the quarter mile time for the locomotive would be about six times as much -- or one minute and 30 seconds.

However -- That seems a bit long, even for a locomotive.

Any thoughts out there?

 

 

[edbenton]

You need to remember though that Electric motorors have the best Torque at Zero RPM.  Given a flat track Passenger train gears less than a minute.  Now for a F40 less than 40 Seconds.  Sorry I have ridden behind them at Metra they fly in accelration. Remember once they are rolling momentum takes over. 

[timz]

RailroadDoc

the propulsive power ratio would be about six times as great for the mustang as the locomotive -- which suggests that the quarter mile time for the locomotive would be about six times as much -- or one minute and 30 seconds.

However -- That seems a bit long, even for a locomotive.

Indeed it is-- a locomotive could do a standing-start quarter-mile in 90 seconds with a good-size passenger train. I doubt anybody's going to be able to give you an accurate answer for a light engine-- we don't know the engine's rate of power buildup. Offhand guess would be 40-50 seconds.

You are only asking about diesels-- not electrics?

[RailroadDoc]

 

Haven't given any thought to electrics -- probably because I don't know their "hp" and weight off the top of my head.

I agree that a passenger train accelerates quite a bit faster than taking a minute and one-half to go a quarter mile.

Does anybody off the top of their heads know the starting tractive effort for a 4000 hp diesel electric?

[oltmannd]

A 4000 HP locomotive with 35% adhesion, assuming a "hole shot", 24 seconds, 57 mph.

[samfp1943]

I guess if you can get a back-hoe to 82mph you could get a locomotive to drag race as well.

http://www.youtube.com/watch?v=c9yfaTlRA7w&feature=fvw

Seems like the really intense gear heads wil get anythng down the track in record time!

[oltmannd]

A similar electric, assuming it could do double the HP rating in the short time, 20 seconds, 73 mph.

[timz]

oltmannd

A 4000 HP locomotive with 35% adhesion, assuming a "hole shot", 24 seconds, 57 mph.

If that's calculated, what are the assumptions?

I checked my records-- a GP40P-2 with two gallery cars (supposedly ~70 tons apiece) did the quarter-mile in just under 40 seconds (specifically, 0.186 mile in 32.72 sec, 0.301 mile in 42.72 sec). So 30 seconds running light looks within reach.

You'll have to decide on the rules-- is the engineer allowed to throttle up with the brakes applied? Do you start the stopwatch when the throttle moves out of Idle, or when he releases the brakes and the engine starts to move?

[blue streak 1]

To muddy the waters. Septa's specifications for the Silverliner 5s call for acceleration to be limited to 3MPH/sec to 80+mph so 0 - 60  = 20 seconds 0 - 80  =  27 seconds for passenger comfort. Slowing was over 4MPH/sec emergency braking.  I imagine the limiter circuit will be cut out during acceptance tests to see how fast they can accelerate. 

[timz]

blue streak 1

0 - 80  =  27 seconds

Maintaining 3 mph/sec all the way to 80 mph would demand something like 4000 hp per car. Are they hoping for that?

[oltmannd]

Assumes adhesion limit up to HP curve. Rated HP available at time = 0, presumably, locomotives loaded against independent brake to get a 'hole shot'. If the start is with the throttle at idle, then you'd have to add another 10-15 seconds for a DC EMD and 40-60 seconds or so for a GE.

[Thomas 9011]

Interesting topic.I always thought it would be interesting if you could gut a old F9 and put a couple monster truck tires on it.Speed on locomotives depend a lot on gear ratios.I can't remember; but I believe the larger the gear on axle the faster the locomotive will take off.SD40-2's are the quickest loading locomotives I have ever been on.They can go from a stand still to running speed in a few seconds.GP38-2s are also pretty quick.GE locomotives tend to load up pretty slow although I am not sure how the newer ones are doing.

As far as electric locomotives go.I remember reading a story on the Milwaukee road Bi polar locomotives.A engineer said he would win bets with brakemen by betting they could not get on the ladder once he put the throttle in gear.He said they moved so quickly once the throttle was moved even if you were standing next to the ladder it would move too fast to get on.

[Paul_D_North_Jr]

The GG1's on acceptance trials did 0 to 100 MPH with 1 coach in tow in about 60 seconds, if I recall correctly.  If I have a few minutes at lunch today, I'll look that up to confirm it.  We'd have to do some physics math to see where it would be after 1/4 mile, but that would be a contender, I believe. 

And - what about the AEM-7 'toasters' / 'Swedish meatballs' ?  My goodness, they have 7,000 rated HP on B-B trucks with only 101 tons - that's almost 70 HP/ ton. 

And/ or Bombardier's HHP locos - I'm not as familiar with their specs, though.

- Paul North. 

 

[garyla]

Funny thing to contemplate. 

Anyone else trying to picture Don "The Snake" Prudhomme and Shirley "Cha Cha" Muldowney in blue-striped overalls, racing for the factory teams from EMD and GE?

[oltmannd]

Paul_D_North_Jr

The GG1's on acceptance trials did 0 to 100 MPH with 1 coach in tow in about 60 seconds, if I recall correctly.  If I have a few minutes at lunch today, I'll look that up to confirm it.  We'd have to do some physics math to see where it would be after 1/4 mile, but that would be a contender, I believe. 

And - what about the AEM-7 'toasters' / 'Swedish meatballs' ?  My goodness, they have 7,000 rated HP on B-B trucks with only 101 tons - that's almost 70 HP/ ton. 

And/ or Bombardier's HHP locos - I'm not as familiar with their specs, though.

- Paul North. 

 

How about 16 seconds, 95 mph (assuming 35% adhesion and 10,000 HP short time)?

[oltmannd]

Paul_D_North_Jr

The GG1's on acceptance trials did 0 to 100 MPH with 1 coach in tow in about 60 seconds, if I recall correctly.  If I have a few minutes at lunch today, I'll look that up to confirm it.  We'd have to do some physics math to see where it would be after 1/4 mile, but that would be a contender, I believe.

That works out to about 22 seconds and 61 mph. (10,000 HP and 400 tons - good assumptions?)

[Paul_D_North_Jr]

A little better data, per William Middleton's books at that classic photo of prototype No. 4800 standing tall at the Claymont, Delaware test track are - 64.5 secs. to 100 MPH, max. of 115 MPH.

Assuming constant Acceleration, that's 100 MPH / 64.5 secs. = 1.55 MPH / sec.

Since 1 MPH = 1.47 ft. per second, that's 1.55 x 1.47 ft. per sec./ sec. = Acceleration of 2.28 ft./ sec./ sec. [sec.**2 or sec.^2 or sec. 'squared', etc.]

Using the formula D = 1/2 x A x T^2, and knowing D = 1/4 mile = 1,320 ft., and A = 2.28 ft./ sec.^2, then rearranging and solving for T = Square Root (2 x D / A) = Square Root (2 x 1,320 / 2.28) = 34.0 secs., at which point the speed / Velocity by the formula V = A x T would be 2.28 ft./ sec. x 34.0 secs. = 77.5 ft./ sec. / 1.47 = 52.7 MPH. 

It's not much different even using the 60 secs. per my original post above.  What would be more useful would be to know the distance that the G-motor covered while getting up to the century mark, and/or the 0 to 60 MPH data, if that can be found someplace.

Don, the 10,000 HP is as good an assumption as any for that very short-time rating - they are often stated to have a short-time rating approaching that figure, and I believe on dynamometer tests they actually recorded around 9300 HP at around 50 MPH - that particular graph is atypically hard for me to interpret. 

But I think the weight figure is high - GG1 No. 4800 was 475,000 lbs. per http://www.steamlocomotive.com/GG1/#specs = 237.5 tons, plus say 70 tons for the coach = 305 tons or so.  So, the nominal power-to-weight ratio is 10,000 HP / 305 tons = 32.8 HP/ ton, only about half that for an AEM-7 running 'light'.  The same website also says the GG1 took 65 secs. to reach 100 MPH, had 10,000 DBHP, and 50,500 lbs. on each driving axle = 303,000 lbs. total. 

At these performance levels, adhesion may be a limiting factor for the first few seconds - let's see:  305 tons gross weight x (2.28 ft. sec.^2 for Acceleration / 32.2 ft/ sec.^2 for Gravitational constant) = 305 x 0.071 = 21.6 tons of tractive force needed = 43,200 lbs. / 303,000 lbs. on drivers = only 14.3 % adhesion needed, so OK.

However, the adhesion limitations mean that it would not be able to use the full 10,000 HP until well under way.  For 25 % adhesion back then x 303,000 lbs. on drivers = 75,750 lbs.; but the same source says 65,500 lbs. with 24:77 gearing - same as for the 100 MPH timed run = 21.6 % adhesion.  So using that figure, and knowing that 10,000 HP x 550 ft.-lbs./ sec. per HP = 5,500,000 ft.-lbs./sec., then dividing by the 65,500 lbs. MAX. TE = 84.0 ft./ sec. when it would be fully utilizing its HP; divide by 1.47 to get MPH = 57 MPH, about the same as either of the speed figures above, within 5 MPH.  So the GG1 would be spinning its wheels most of the way down the quarter-mile track . . .

Going back, then, and recomputing on the basis of the TE / adhesion limitation as governing, I get the following -

TE/ Gross Wt. = 65,500 / 305 tons x 2000 lbs. = Acceleration = 0.107 of Gravity constant of 32.2 ft./ sec. = 3.46 ft./ sec. = 2.35 MPH / sec.

Plugging that A into the 1/4 mile suare-root formula above, I get T = 27.6 secs., and V = 27.6 x 3.46 = 95.5 ft./ sec. = 65.0 MPH.

So I can see the 61 MPH range for the speed across the finish line, but not the 22 seconds - more like 30 seconds or so, I believe.

Anyone feel free to correct or critique anything - I don't do this often or for a living, so no pride or professional status is at risk here.

Fun stuff - would make a good exam question for a course in physics, mechanics, or dynamics, I think.

- Paul North. 

[oltmannd]

I was too lazy to do all the math, so I built a spread sheet model with one second increments....

[carnej1]

Here's my entry:

http://www.darkroastedblend.com/2007/01/jet-powered-other-futuristic-trains.html

Maybe I can get Craig Breedlove (former land speed record jet/rocket car driver) to run her...

[Paul_D_North_Jr]

garyla

  Funny thing to contemplate. 

Anyone else trying to picture Don "The Snake" Prudhomme and Shirley "Cha Cha" Muldowney in blue-striped overalls, racing for the factory teams from EMD and GE? 

Shirley Muldowney - http://www.dragracecentral.com/drcstory.asp?ID=110424 

[samfp1943]

The Pennsy's S1 was a favorite of mine since I did a paper on it several years back.  I had read a statement by Raymond Loewy made as he stood track side in a station in Ohio as the S1 came through at speed. It really blew me away. So I thought since this top was about Speed and power this might be of interest:

http://www.absoluteastronomy.com/topics/PRR_S1 

FTS: "... (nicknamed "The Big Engine") was an experimental locomotive that was the largest rigid frame passenger locomotive ever built.

FTS: "It was hoped that the locomotive could haul 1,000 tons at 100 miles per hour, but this goal was not reached. There are apocryphal stories of the S1 reaching or exceeding 140 miles per hour, but there is no documentation of this and it is considered unlikely by experts..."

And some more about the PRR and Raymond Loewy at:

 http://www.statemaster.com/encyclopedia/Raymond-Loewy 

(Drop down the section labeled Pennsylvania Railroad)

 

Another website is linked here:

 http://www.idsa.org/absolutenm/templates/?a=289

Describes the evolution of the designed for streamlined locomotives for the Pennsy(PRR) and NYCRR.

 

 

 

 

 

[RailroadDoc]

Thanks to everybody for their input. . . . it's a fascinating discussion. . . .all that needs to be done now is to to actually have some drag races -- GE vs. EMD, AC vs. DC. . . .

I wonder if we could get Mythbusters to do a program on this?

[Grantham]

The only organised drag race I've heard of between trains was timed runs by shays...

[Grantham]

The only organised drag race I've heard of between trains was timed runs by shays...

[Cricketer]

Somewhere in the back of my mind is a memory that a steam galas (or maybe just the one gala) in central Europe - Hungary comes to mind - they still do drag races. Not sure if anyone else can track this down - I'll see what I can do looking at old magazines.  

 

[sfcgadget]

These Shays won't break any records, but this race sure looks great.

http://www.youtube.com/watch?v=h4I0pDd2OvI

[wrawroacx]

I caught this about a month and half ago in Berea Ohio and I think this counts as drag racing for trains for sure - http://www.youtube.com/watch?v=anVNEEkgjEI