Why do Class 57s scream?

[Harbornite]

Not a class 37 but....

https://youtu.be/ex4HAZEQ4UQ

Good video that.


If anyone wants to see EMD clag, watch this. Awful stuff.

https://m.youtube.com/watch?v=wXpTRpn_fuQ

 

[ac6000cw]

I'm a bit dubious about that last one - the cab markings clearly show that
the loco has been fitted with a BOSE sound system to enhance the bass!

MARK

Actually I've never heard a recording that really does them justice - 'in the metal' at the lineside they produce a lot of very low bass which you feel as much as hear (you would almost need 'Sensurround' at home to reproduce it ). I did once see/hear one of their V16, 6000hp AC6000CW antecendants - that really was mean sounding...

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If anyone wants to see EMD clag, watch this. Awful stuff.

https://m.youtube.com/watch?v=wXpTRpn_fuQ

Although it's nothing like as bad as with the old SD40/SD45, the modern stuff with computerised fuel injection and engine management can still produce a cloud of 'clag' as it exits that tunnel - I noticed it last year when I was standing at Bealville looking up towards the tunnel. (I managed not to be pointing the camera in the right direction to video it happening - doh!)

 

[Highland37]

Good video that.


If anyone wants to see EMD clag, watch this. Awful stuff.

https://m.youtube.com/watch?v=wXpTRpn_fuQ

Wow. Are those SD40-2s?

My basic understanding was that you couldn't load a DC traction motor as much as low speeds but AC will take anything you give it. But that train wasn't going very fast.

 

[Harbornite]

Wow. Are those SD40-2s?

My basic understanding was that you couldn't load a DC traction motor as much as low speeds but AC will take anything you give it. But that train wasn't going very fast.

Aye they are, of Southern Pacific Railroad.

AC seems to be preferred now for new freight diesel locos (or should I say units) in North America.
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Although it's nothing like as bad as with the old SD40/SD45, the modern stuff with computerised fuel injection and engine management can still produce a cloud of 'clag' as it exits that tunnel - I noticed it last year when I was standing at Bealville looking up towards the tunnel. (I managed not to be pointing the camera in the right direction to video it happening - doh!)

Ah I see, I can imagine that happening as the tunnel prevents fresh air from getting in, thus allowing the smoke to keep on circulating.

 

[fowler9]

I always thought the screaming sound was down to the turbocharger which looks a lot like a jet engines fan blades. Apologies if someone has already answered this, it didn't appear to have been already answered on a brief inspection.

(Edit) I think someone answered it pretty early on and it is the big turbos. Ha ha.

 

[ac6000cw]

Wow. Are those SD40-2s?

My basic understanding was that you couldn't load a DC traction motor as much as low speeds but AC will take anything you give it. But that train wasn't going very fast.

From the numbers, the loco consist on the front is SD40T-2, SD45T-2, SD45T-2, SD45T-2 (Cotton Belt was a Southern Pacific subsidiary). The SD45 is roughly an SD40 fitted with a 3600hp V20 645 engine, and the 'T' means it's a 'tunnel motor' variant with the air intakes situated low down on the hood, so they pull in cooler air in tunnels (instead of re-cycled engine exhaust!). SP had a lot of tunnels and showsheds on its system...

EMD DC drive locos had a 'minimum continuous speed' (usually about 13-14 mph as far as I know), below which they can only operate at high power for limited periods of time.

AC drive locos don't normally have that limitation, so maximum tractive effort is usable basically down to a standstill for hours on end (if you are desperate, like a loco has failed in the consist) - that's why they are the heavy-haul tool of choice these days. As an example of what they can do, 10 years ago 'Trains' magazine reported that a pair of 'heavy' GE AC4400CW had pushed a coal train in a sub-zero snowstorm for 90 minutes at less than 2 mph while producing near maximum allowable tractive effort (190,000 lbs per loco) - it got to the top of Cranberry Grade (in W.Virginia) slowly but surely... Those two-unit 'heavy' AC drive helper sets had replaced earlier three-unit EMD SD50/SD60 DC drive helper sets on that route.

 

[Cowley]

From the numbers, the loco consist on the front is SD40T-2, SD45T-2, SD45T-2, SD45T-2 (Cotton Belt was a Southern Pacific subsidiary). The SD45 is roughly an SD40 fitted with a 3600hp V20 645 engine, and the 'T' means it's a 'tunnel motor' variant with the air intakes situated low down on the hood, so they pull in cooler air in tunnels (instead of re-cycled engine exhaust!). SP had a lot of tunnels and showsheds on its system...

EMD DC drive locos had a 'minimum continuous speed' (usually about 13-14 mph as far as I know), below which they can only operate at high power for limited periods of time.

AC drive locos don't normally have that limitation, so maximum tractive effort is usable basically down to a standstill for hours on end (if you are desperate, like a loco has failed in the consist) - that's why they are the heavy-haul tool of choice these days. As an example of what they can do, 10 years ago 'Trains' magazine reported that a pair of 'heavy' GE AC4400CW had pushed a coal train in a sub-zero snowstorm for 90 minutes at less than 2 mph while producing near maximum allowable tractive effort (190,000 lbs per loco) - it got to the top of Cranberry Grade (in W.Virginia) slowly but surely... Those two-unit 'heavy' AC drive helper sets had replaced earlier three-unit EMD SD50/SD60 DC drive helper sets on that route.

190000ibs. Blimey! And we think 60s are powerful.
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Not a class 37 but....

https://youtu.be/ex4HAZEQ4UQ

Phwoar. I just had a 'moment' listening to that.

Going to run it through my amp and speakers in the morning before work and see if I can wake the house up with it turned up to 11!

 

[Flying Snail]

I always thought the screaming sound was down to the turbocharger which looks a lot like a jet engines fan blades. Apologies if someone has already answered this, it didn't appear to have been already answered on a brief inspection.

(Edit) I think someone answered it pretty early on and it is the big turbos. Ha ha.

Here are a pair of IE 121s with smaller non-turbocharged 8 cyl EMD engines.

https://www.youtube.com/watch?v=ohvqXrm4hXY

Lovely noise, to me anyway.

 

[ac6000cw]

190000ibs. Blimey! And we think 60s are powerful.

On the other side of the coin, those 'heavy' AC4400CW weigh around 195 tonnes (32.5 tonne axle load), so relative to their 130 tonne weight the 60s don't do too badly at 106,500 lbf (max) for a DC drive design.

I don't know how far a 60 has ever been tested in terms of train weight, but (to quote from Wikipedia) a class 59 holds a record:

"On 26 May 1991, 59005 set the European haulage record for a single locomotive, with a stone train weighing 11,982 tonnes and 5,415 feet (1,650 m) long."