CN 149 lead by a pair of howling sd70m-2's head past lovekin on dec 30,2010 Filmed with Nick (widecabfan) Jay (crazeejay2006) Mike (trainboi21 ) Mike (TheEtobicokeRailfan) Cam (admydragon) Tyler (osrx1) Dan ( dan9325)
This noise is not coming from the fans, as someone has said, they'd blow apart long before they'd ever make a noise like this. I thought it was the fans for the longest time too, it is absolutely not natural for a locomotive to make that much noise. Also if it was the dynamic braking fans, you'd surely hear this in all the units, but it is very clearly coming from the auxiliary locomotive, not to mention both engines are running wide open. What it most certainly is, is a turbo fan that is off balance, could be caused by anything ranging from shot bearings, carbon deposits, or just a damaged blade from wear and tear. Ever used a Dremel tool with a small cutting disc? Ever turned the RPM too high and noticed a heavy vibration with an awful loud noise? Imagine that, but with a giant turbocharger, bingo, that's your noise.
To say it in layman’s terms it is a mechanical blower that pushes air into the cylinders. 12 16 or 20 645 or 710 engines… Because the engines are a two stroke diesel they have a compression and a power stroke and the intake air charge must be forcibly input into the cylinders and forcibly ejected so therefore it is a blower or compound turbo supercharger that provides the push and scavenge of exhaust gases… Aka a Roots Blower on the old 567s
SD70M-2's and SD70ACE's have different cooling fans. CN and NS both have the same cooling fans on there SD70M-2's. and SD70ACE's all have varying cooling fans.
Can someone tell me what that howling noise is coming from? Failing turbo? Cooling fans? Heard one today with a howl but they kept revving it up & down.
It's the cooling fans for the dynamic brake. I'm not sure why they are loud, it may be the design of them (chopping up the air too much, like a siren), or they may be spinning very fast to move a lot of air.
