The sound of steel wheel on steel rail...

as a train aproaches you can hear a pinging sound comming from the rails. what is it ? is it the sound of the steel straining from the weight and forward movement of the train ?

I always thought it was the sound of the train crossing over the joints in the rail transmitted along the length of the rail. I could be wrong...

Conrail71 is correct. It was more obvious in the NYC subways. The pinging noise came after the conversion to CWR began.

It is my understanding it is from wheel slip. There is no differential on a railroad truck axle. When any sort of curve is encountered, one wheel is turning faster than the other and something has to give, either one wheel spins slightly or the other slides along the rail. On a gentle curve, you'll just hear a "ping", but on a sever curve you'll hear a "squeal".

if the rail has a sharp wineing sound like a few thousand misquetos in a tangent section of rail it is a sign that the rail was reshaped by a rail grinder with in the past few days or so.

scharnhorst wrote:if the rail has a sharp wineing sound like a few thousand misquetos in a tangent section of rail it is a sign that the rail was reshaped by a rail grinder with in the past few days or so.

Either that or there are a few thousand mosquitos hovering around you...

Brad Smith wrote:It is my understanding it is from wheel slip. There is no differential on a railroad truck axle. When any sort of curve is encountered, one wheel is turning faster than the other and something has to give, either one wheel spins slightly or the other slides along the rail. On a gentle curve, you'll just hear a "ping", but on a sever curve you'll hear a "squeal".

Not true, the wheels are tapered. When a curve is encountered the wheels shift toward the outside of the curve. The taper makes the outside wheel larger in effective diameter and the inside wheel smaller in effective diameter, and the axle goes around the curve without sliding. If there is other forces in play also, such as with long cars or high speeds the axles will be forced out far enough to cause the flange to rub against the inside of the rail. That results in a very high pitches squeal or pingging sound.

it has nothing to do with curves in the track. this is along a three mile straight away on a mainline. (around cp 390 if anyone is wondering). trains reach a speed of 50-60 mph. 80mph for amtrak.

its on welded rail so i dont think joints come into play.

I've noticed this too, and only on welded rail. The rails starting "singing" as a train approaches.

dummy wrote:its on welded rail so i dont think joints come into play.

There are joints in CWR, just very far apart. CWR is under tension which is why the slightest knock from the wheels hitting a joint, or even a weld that is not 100% smooth, causes the pinging.

scharnhorst wrote:if the rail has a sharp wineing sound like a few thousand misquetos in a tangent section of rail it is a sign that the rail was reshaped by a rail grinder with in the past few days or so.

Not necessarily... I noticed the "ping" or "squeal" on the orignal B&H mainline in Hammondsport... and that line never saw a rail grinder while I lived there (full time '76 to '87, part-time '87 to '91). Nor was the rail CWR. Methinks another explanation is in order.

There are "other" moving parts in regard to rail structure. as a train passes over a fixed point yopu'll see the rail dip from the weight of the car. The cars weight depresses the rail onto the tie plate and tie. The spikes are set and as the weight depresses the rail the spike is rubbed slightly and occasionally catches causing a ping as the rail slips ever so minutely. This also occures between tie plate and rail, again with a ever so minute gap between the two. Since CWR is a long, single piece, the sound travels very well and swiftly.

I noticed this one day some 20 years ago , when i was standing behind a steel mesh fence , besdie the tracks . The fence seemed to accutene(sp you know what i mean ) the noise , and i heard it quite a long time before i heard the rest of the train noise .
so far , the rail moving through the spikes seems to be the most plausible explanation to me .

this video seems to capture some of the sound
http://www.youtube.com/watch?v=V_Q3UmAP ... ed&search=