Derspite the small efficiency gain from the improved aerodynamics (drafting effect), I can't see why ten locomotives ganged together, on flat ground, would have a higher top speed than one all by itself. Most modern diesel electrics are gear-limited, and can achieve top speed even while pulling a train. 6,200 HP is a lot.




https://www.miataturbo.net/attachmen...ine=1454354432

serves me right for not crediting the original video.

depends on whether or not one locomotive can reach its max speed. Thats like saying a bugatti veyron has the same top speed whether you keep the v16 in it or swap in a B6 engine.

No, it's not like that. It is, however, like saying that a stock NB has the same top speed as one making 250 HP. Because it does.

When we say that a vehicle is "gear limited," we are saying that the maximum speed of the vehicle is limited not by the amount of power that its engine can produce relative to its aerodynamic drag, but by the gearing of the drivetrain relative to redline RPM.

Assuming that they have the same transmission, differential and rear-end, a stock NB and an NB producing 250 HP both have the same top speed, because the stock NB is fully capable of reaching redline in 5th or 6th gear. It just takes longer to get there.


The loco shown in the pictures is a GE Evolution series, which is primarily used in freight service. I'm not sure which specific model (they range from a 4,400 HP V12 to a 6,200 HP V16), but they are all geared for 70-75 MPH. The higher HP models simply have more dead-weight (towing) capacity and are better suited for use on western routes where they deal with greater inclines.

The GE Genesis series passenger locomotives (which is what I used to ride every day when I lived upstate) use a related family of engines and drivetrains, but in that application, they're geared for 110 MPH at the expense of a lower towing capacity. Passenger trains tend to be much shorter and lighter than freight trains, and demand greater speeds.




https://www.miataturbo.net/attachmen...ine=1454358157

Which is why i said "it depends on if one locomotive can reach its max speed". Which is different wording for "it depends on if it is gear limited"

Which is exactly what I said in the first reply I made on the subject, post # 27221. "Most modern diesel electrics are gear-limited."


https://www.miataturbo.net/attachmen...ine=1454361890

Which was a ninja edit made after my initial response

Attachment 237504

Fair enough.

It took a minute for my brain to say "wait a sec, no that's wrong. The drift effect will improve per-loco economy slightly, but unladen top speed isn't limited by HP on these things like it was back in Doc Brown's day."


https://www.miataturbo.net/attachmen...ine=1454364882

And here I was thinking I had finally been smarter than Joe P :)

Time to go delete all the screenshots of proof recorded in case my genius was edited by a moderator.

ouch
https://www.youtube.com/watch?v=ybx2...ature=youtu.be

How many different layers and filters did I use on this grainy, under-exposed cell phone shot taken while on my way home this evening?


https://www.miataturbo.net/attachmen...ine=1454373232






Unrelated:


https://www.miataturbo.net/attachmen...ine=1454373232

I've used this one in the past, works great for allergies when mowing the lawn :likecat:

https://www.miataturbo.net/attachmen...ine=1454374110

I'll bring my big camera to NYC if you wear a red wig for me...

:party:

I'll be able to get more than a few strands of hair in focus.

Do this with a white shirt and yell allahu ackbaaar See what happens :D

Exceeded the wing load and sheared off a wing at an airshow but BRS parachute saves his ass (Jump to 2:00):