A gearbox for a little locomotive

[Admiral_dk]

First - Congratulations for your new Sound from the Loco / Engine - it has a certain realism to it 

i was assuming, from what i have read and understood, (model engines are far from my academic degrees!) that with a longer stroke, my engine will give its peak torque at lower rpm, nearer from the wished "put put put put" and not the usual screaming note.

This is one of those Urban Myths that are imposible to kill 
You got the same pressure and if it is applied to a bigger surface, you have more power, but multiplied to a shorter stroke => same Crank output - and Vice Versa ...!
The true difference can be the Fuel/Steam consumption .... (but also other factors are in play here).

Per             

[RReid]

The engine runs very well, and sounds great! Congratulations, Zephyrin!
The muffler must work quite well, it would be interesting to hear "with" vs "without".
edit - Sorry, I overlooked the prior video that does just that. A significant difference!

[Kim]

Very effective muffler!  And interesting experiments to measure the noise level. Thanks for sharing those with us. 

She runs really nicely and makes a great put-put sound!

Kim

[Zephyrin]

 thanks for the comments, much welcome !
yes I love the put put sound, at last i feel a progress in this direction...
I will not do this sound test again as the muffler becomes rapidly really hot, and I burn my fingers...

a well of science as always Per, thanks , great to have a clear view on so many topics, as my engine is not yet complete...