Freight train noise?

Question

the other day one of the engines of a passing train sounded really strange. it kinda sounded like a cars bass system turned up really loud. i was half asleep at the time but when i looked out the window there was no cars driving by. it was the train making the noise. in all my years living here i never heard a freight train make that kind of noise. what could've made it make that noise?

Answer 1

My guess would be you live near a line that sees EMD's almost exclusively, and that night a GE was on the train.

The General Motors Electro-Motive Division locomotives have a much different sound than GE's..much smoother and continuous. Most have 2 cycle engines, aside from the newest ACe's, but they are quiet.

General Electric locomotives are known for the chugging of their 4-cycle engines. The chugging is slow with a heavy bass sound to it when idling, and when the engine is revved up, it gets louder and the faster the engine goes the less decernable each chug is making it a big pounding bass sound.

I live near a line of a railroad that uses GE's almost exclusively and actually like that sound over the EMD engine.

Answer 2

Locomotives on a freight train makes lots of noises for lots of different reasons.

A locomotive at full throttle, or close to it, will make a loud, low pitched rumble that varies depending on the manufacturer, and the particular model.  Even at idle, the different models sound different.

Another possibility is dynamic brakes.  That's a little more high pitched than the prime mover under power, more of a whine than a rumble, with varying degrees of volume depending on the load.

Without hearing the sound itself, it's hard to pinpoint, but these should give you some good ideas.

Answer 3

Actually I've heard that same noise too. No joking, I have.

It almost sounds like something attached to the wheel and each time it rotates and hit's the steel track that "bump" or "boom" sound happens.

My mechanical inclination tells me it could be something in the functioning parts of that particular car.

Meaning the wheels, the engine, something in the engine. But I'm inclined to think it's in the wheels.

You know the wheels on a train are one piece. The two outer rollers which roll on the track and the shaft that connects the two wheels.

I'm not answering simply to agree with you...........I truly have heard the same sound. So, you're not just "hearing" things.

One more thing about trains. Tornados sound like freight trains. I've heard a tornado, not on the ground but in the air and not yet touched down, and it sounds just like a freight train.

Answer 4

sound like some wheels may be slid flat

Answer 5

I think you may have heard a turbocharger clutch gone bad.  They make a sound similar to what you have described.

EMD prime movers have turbochargers, but, up through run 5, they are gear driven, just like the older roots blowers.  In run 6, a clutch is supposed to disengage, and then the device operates as a true turbocharger, being driven by the force of the engines exhaust, in run 6, 7, and 8.  This type of failure is usually accompanied by thick smoke belching out of the stacks.  Sometimes they'll settle down, sometimes they won't.  

When working on the things over a long period of time, you hear a lot of them gone bad.  But as a track side observer, you could wait a very long time before you see or hear one.