Din - the extra heat in superheated steam prevents as much of it from condensing as it gives up its energy during expansion, which makes the exhaust dryer, and provides more remaining energy available to be expended in the exhuast system in the creation of vacuum in the front end. So, there's a LOT of stuff that happens after the throttle........

dave

I heard an interview with Little Richard one time and he attributed the beat to his music to the steam engines he heard going by his grandmother's house as a kid.

.

Yep! And pretty much every chuck song has the same beat!

Just a clarification....though its easy to mistake it for a Banshee, the I1 is actually wearing the 3-chime whistle in that track. It doesn't have that typical Pennsy sound because the whistle is overblowing on the 3rd note when he pulls the cord all the way. That produces the high-pitched shrieking, which is so loud it almost drowns out the sound of the other 2 notes. But if you listen closely around 2:32...when the engineer eases off the whistle cord at the end, AND in the resulting echoes...you can hear 3 notes being blown: E-G#-B....a typical chord structure for the passenger whistles.

I actually like the overblown sound....just listen to those echoes! Imagine hearing that at night!

You are correct on the overblown chime. I've blown two different Pennsy 3 chimes and they are gorgeous, but it would be easy to mistake the single note.

Reading and Northern 425 has the sharp (crack) exhaust of superheated engines.
http://www.youtube.com/watch?v=XvtW65QA0d0

And lets not forget the T-1
http://www.youtube.com/watch?v=Z6Xp5hJwKC8

Low Note, I took a look at your blog post, and it wouldn't surprise me if you have something, though of course with most if not all of the musicians involved being long gone from this world, you can't ask them about this.

Still, that "train beat shuffle," does have the sound of an engine just slightly, just barely, out of square. Take note of the drummer in this clip from your post, starting at about 0:10:

http://www.youtube.com/watch?v=IutVaM-a ... re=related

Some of the locomotives in the clips I provided sound like that at that speed; in engines that are further out of square than this, you definitely can hear them saying "I think I can, I think I can." This is not necessarily connected to superheated or saturated engines, but is a function of how well the valves have been set. The counterpart to this would be "valve timing" in internal combustion engines, with the valves governed by cams; steam locomotives for the very greater part use a type of sliding valve of either flat or piston configuration, and its timing can be altered in motion with the variable travel valve gear locomotives use, which also reverses the locomotive. Getting the valves set right could be a ticklish job, what with some very long, slender parts that drove the valves, slack in the joints in the valve gear, the necessity of gradually rolling the whole locomotive back and forth to note where ports would open or close, and getting the whole works right for both sides of the engine, and also for forward and backward motion. All this was doubled on articulated power, and three-cylinder locomotives with a conjugating valve gear for the third cylinder (controlling this valve with motion derived from the other two) introduced new challenges in valve setting. The valve-setter was in fact one of the most skilled of roundhouse employees, and his pay and relatively clean clothes reflected this.

It also wouldn't surprise me if variations in exhaust passages also played a role, and as noted, a superheated engine also has a sharper, dryer sound, and that seems to play out in the drummer demonstration above as well. All of this, and other sounds, would be very common in the world of the 1920s and later. They would have been a part of everyday life, a part of the landscape itself in that time.

I'm not a musician, but it has been said that most steam locomotives would have a strong "four beats to the bar" beat; this is in reference to four exhaust beats per revolution of the drive wheels, brought about by a combination of crank pins set 90 degrees apart on opposite sides of the locomotive to prevent stopping on a dead center, and the alternating front and rear exhausts from double-acting pistons. Ideally these would sound nice and even or "square,", but of course this was not always the case.

There is another common 4-beat sound in railroading, and that is the sound of 4-wheel freight car trucks on jointed rail. The is the "clickity-clack sound kids used to be so familiar with, and here it is, combined with Doppler-effect whistles and fast-running guitar "shuffles" as you call them, in "Fast Freight," by the Kingston Trio:

http://www.youtube.com/watch?v=Q1rWyyYf ... re=related

Enjoy!

I know too !!@#$%&!! much--and as a result, I get steamed at Hollywood movies. . .

SteamPWR had a couple of neat clips there.

The Reading & Northern's No. 425 not only has a nice, sharp exhaust, it also is quite close to being square--none of that "I think I can" loping on this engine.

The Reading T-1 is pretty square, too, and also illustrates a couple of other characteristics in steam locomotive sound. One is that the exhausts occur at 90-degree intervals with the drivers; this is because of the valve timing relationship with the engine. The puffs of smoke from the stack also are in synch. In short, a steam locomotive has a visible as well as audible "dialogue," and I can't tell you how many times I've seen movies where the synchronization is off. Some of these off-beat sounds look as bad as the dubbed dialogue in the Steve Reeves movies in which he played Hercules. Ugh!

The T-1 sequence also illustrates the sound of loose rod bearings, a distinctive mechanical "clunking" sound.