The Fallingwater Train Whistle Mystery | Hey Ray!

PITTSBURGH (KDKA) - We have ourselves a mystery!

Rhonda asks: I work at Fallingwater. Why does it seem like the only time you can hear the train whistle is when it is going to rain?

So, we have a couple of clues: You hear a train and then it rains. We will need more clues than that to get to the bottom of this!

Let's look at a map of the area, to see if we can figure out why this happens.

You can see that Fallingwater is located a little east of the Youghiogheny River. Along the river, we find our train tracks. That is where the train sound is likely coming from.

Now the train tracks wind with the river. The tracks to the north are about a third of a mile away. The tracks due west are about a half mile away.

The tracks to the southwest are about a quarter of a mile away.

So, we know there are tracks, but there are other factors that impact sound.

This area has trees and hills. These can change sound direction and even absorb sounds. We have a lot of elements here, but I think we can put together a good hypothesis of why Rhonda can hear a train before Fallingwater gets rain.

A change in wind direction often accompanies rain, especially when the rain is driven by a cold front, so I think this is also a big factor.

Wind direction has a big impact on sound. When the wind is blowing away from you and toward the sound, the sound waves are forced upward.

When the winds are blowing from the sound toward you, this forces the sound downward, making it audible to you.

If Fallingwater had a traditional, or zonal, wind flow from west to east, the sound would have a longer way to travel and would likely be absorbed by the trees and redirected by the terrain.

However, when winds come from the southwest, the train is close enough to be heard with the wind pushing the sound down. I also think the southwest wind and Fallingwater's proximity to the train tracks to the southwest are the determining factors here, but what does this have to do with rain?

When a cold front is approaching, winds would typically come from the southwest. Those southwesterly winds help the sound from the closer section of train tracks travel over trees and terrain, carrying the train's sound to Fallingwater.

That cold front then stirs up rain.

It is either that or the train's engineer blows the horn to let you know it is going to rain!