Nippon Sharyo bilevels for Amtrak corridor trains

David Benton wrote:Tgv duplex = 38 tonne , or 83,600 lbs .Actually could be less , i divided the trainset weight by 10 .
You might also want to check out the relationship between weight and speed . double the speed you raise the force by 8 times i think . so a 125 mph passenger car may do more damage than a 60 mph coal car .

The TGV Duplex cars are not 85' long are they?

No, they use the metric system....

(just having a little fun here)

Tadman wrote:No, they use the metric system....

(just having a little fun here)

yup , go alot faster in metric , 200 km/h.

110 MPH = 177 KPH?

I doubt if the midwest cars will see greater than that speed. It is good to see cars coming out of Illinois!

200 clicks is 125 mph .

I'm curious, will Amtrak be running locomotives on both ends of the trains on these 110 mph corridors (as has been the case on the Michigan line since going to 110 mph)? I note that the Illinois 110 mph demo runs have had locos on both ends.

And if this new bilevel order includes cab cars, will they be flat-ended cab cars like the existing California/Surfliner cars or will they have sloped ends for crashworthiness and/or aerodynamic considerations?

Hey, there will be some AEM-7s becoming available soon. I bet they'll be a whole lot easier to maintain after their traction motors have been removed. Why not send them out to the Midwest as NPCUs? At least until their leases run out.

I don't think you could even go 125 mph with a slab front end . you would just get into a doubling of horsepower per mph scenario , or even to the power of 10 . and i'd hate to think of the turbulence created .
I think the ordering of these cars has signalled that 110 mph is it for the next 30 years .

David Benton wrote:I don't think you could even go 125 mph with a slab front end . you would just get into a doubling of horsepower per mph scenario , or even to the power of 10 . and i'd hate to think of the turbulence created .
I think the ordering of these cars has signalled that 110 mph is it for the next 30 years .

Well, the Metroliner cab cars do run at 125 mph on the NEC portion of the Keystone run - those are almost a slab front end. But I was wondering if there were new crash standards that required cab cars to be designed more like this:

David Benton wrote:I don't think you could even go 125 mph with a slab front end . you would just get into a doubling of horsepower per mph scenario , or even to the power of 10 . and i'd hate to think of the turbulence created .
I think the ordering of these cars has signalled that 110 mph is it for the next 30 years .

Both the Keystones on NEC and the MARC Penn Line trains on NEC in push mode run at 125 mph with cab car forward and the cab cars are more or less flat faced. Power of 10 is a bit of a hyperbole that is not supported by the Physics that applies to this situation BTW.

The new cars are 125mph capable, though there will be no track in that area that will allow them to run at such speeds. The California Cars are also 125 mph capable.

bit of a difference in frontal area between a bilevel and a metroliner cab car , but i will concede the power of ten is possibly over the top , and apologise for that . anyone able to work out the correct ratio ?

David Benton wrote:bit of a difference in frontal area between a bilevel and a metroliner cab car , but i will concede the power of ten is possibly over the top , and apologise for that . anyone able to work out the correct ratio ?

I think the force of drag increases proportionally to frontal area. So doubling the frontal area would double the drag. But drag isn't the only force the locomotives need to act against--there's rolling resistance and friction, too. It's drag is proportional to the square of velocity--that may've been what you were thinking of.

But take that with a grain of salt--though I just took Fluid Dynamics in college, I wasn't too good at it.

The air resistance depends on the shape (form drag) and the length (skin friction).

A teardrop shape is best, but a teardrop lengthens its tail as the speed increases. A bullet shape is second best.

Skin friction along the length of the vehicle is not insignificant for trains, although the aerodynamic drag for one passenger car is a fifth to an eighth of the drag on the locomotive. The following drag coefficients have been calculated for European trains:

Table 3.1 Constants for the calculation of aerodynamic resistance from locomotives (1).
Electric locomotives Air Resistance Coefficient cL,lok
- Four axles, normal shape 0,80
- Four axles aerodynamic shape 0,45
- Six axles, normal shape 1,10
- Six axles aerodynamic shape 0,55
- BR 103 0,50
- BR 112 0,54
- BR 110 0,61
Diesel locomotives
- Four axle 0,60
- Six axles 1,10
- Middle axles 1,00

For wagons, the values in tables 3.2 and 3.3 can be used:
Table 3.2: Constants for the calculation of aerodynamic resistance from passenger wagons (1).
Passenger cars Air Resistance Coefficient cL,v
General 0,15
26,4 m (Standard German passenger wagon) 0,11

http://www.inrets.fr/ur/lte/publi-autre ... b_rail.pdf

Keep in mind, a bilevel doesn't necessarily double the frontal area - it's maybe 30% taller than a standard coach. See link: http://www.trainweb.org/amtrakpix/locos ... 10404A.jpg

ferroequinologist wrote:

David Benton wrote:bit of a difference in frontal area between a bilevel and a metroliner cab car , but i will concede the power of ten is possibly over the top , and apologise for that . anyone able to work out the correct ratio ?

I think the force of drag increases proportionally to frontal area. So doubling the frontal area would double the drag. But drag isn't the only force the locomotives need to act against--there's rolling resistance and friction, too. It's drag is proportional to the square of velocity--that may've been what you were thinking of.

But take that with a grain of salt--though I just took Fluid Dynamics in college, I wasn't too good at it.

If I recall my Physics right.... The drag force is proportional to square of velocity so the power needed to overcome said drag is proportional to the cube of velocity. That is about as high a power you get to .... not anywhere near 10.

The difference in the frontal area assuming flat face is probably of the order of 15 to 20% more going from a single level to a Superliner level car. For single level roughly 14' x 10' = 140 ft sq, Superliner roughly 16' x 10' or 160 ft sq 160/140 = is more like 14%. Given that single level car height generally is a bit smaller than 14' and Superliners a bit more than 16' I think 15% to 20% is probably a good ballpark, though a bit on the high side.