2 -4 chuffs

Your basic two cylinder prototype steam locomotive emits 4 chuffs per driver revolution, whether under power or drifting.

 

Rusty

Real steam locomotives exhaust twice per driver revolution per cylinder.  Thus a typical 2-cylinder locomotive has 4 chuffs per driver revolution.  Lots of 3-railers used to think (some still do) that 4 chuffs is too many at high speeds and the locomotive "sounds like a machine gun."  That is why Lionel originally offered 1 chuff and later 2 chuffs per driver revolution.  Lionel's latest scale locomotives finally have the correct 4 chuffs.  Newer 3rd Rail locomotives come with a slide switch so the owner can select 2 or 4.  MTH locomotives are adjustable via DCS, I think largely as a "because you can if you want to" feature.

 

And if a Simple articulated or a Duplex it more often then not would be some cadence of eight (8).

 

Only the MTH DCS system allows one to adjust from 1 to 16.  TAS's EOB allowed adjusting at 1 or 2 or 4.

The prototype has valves that open to exhaust the steam and then close to end the exhaust. The faster the speed the shorter the time for that chuff.

In the model the sound starts with a switch but is not ended by another switch. Rather the chuff sound is given an arbitrary on time. The model chuffs overlap each other at a much lower speed than on the prototype. Switching to two chuffs  per rev prevents this overlap of chuffs until a much higher speed is achieved. In practice switch engines and freight engines sound better with 4 chuffs. High speed passenger engines benefit from two chuffs. Maybe in the future the sound boards will have inputs to both start and stop each chuff.

 

Pete

When I was a kid, the best sounding chuff was the American Flyer operating piston chuff. Nothing could beat it. Wow we have come a long way....

When I hear that chuff though and smell that smoke I tend to drift in time.

ALL 2-cylinder steam locomotives have 4 exhaust beats for each revolution of the drivers.

Thanks all for your replies.  I thought it had to be 4 chuffs but having only been inside a steamer as a fireman just once, I really wasn't paying attention to the cadance (especially being partially deaf doesn't help).  So the MTH and Lionel allows operators to change chuffs even if it doen't match reality.

I was a fireman for four hours on the hottest day in August at a tourist operation.  I was so busy keeping that oil burner just right and steam at some now forgotten pressure, that I  paid little attention other things.  Believe me, behind that HOT boiler on a hottest day gave me an insight to what that hot place below might be like .  I was never so glad to be off that engine, and joined the adjacent trolley operation the next year where I could have cool air in my face on open air cars.

It's because people tend to run toy trains at ridiculously high speeds that 4 chuffs per revolution "sounds wrong" to them.

 

To be fair I haven't heard a sound system that sounds "right" at high speed, it's like the system is playing a short file on repeat really fast instead of the overlapping cacophony of noises that come from a locomotive at speed.

Oh, I dunno. 

 

When I was running 1630 out at IRM, 4 chuffs per sounded pretty good while at speed.

 

To anyone ever involved with the real thing, 1 or 2 chuffs per just ain't natural.

 

Rusty

I'm not sure you understood my point.  I prefer and demand 4 chuffs/rev myself, but no model train sound system has faithfully recreated the sound of a locomotive at speed. They start to sound like a digital file skipping.  This is obviously unpleasant,  and reducing the chuffs to 2 or 1 per rev is a bad bandaid on a digital problem.

I agree with you Wowak. The best sounding model steam engine at speed, I had was a Williams Niagara with QSI heavy steam sound. Andy Edelman Installed it for me. This was before MTH was on the scene. That was a good sound system. I am referring to engine sound ( chuff ) only.

 

Clem