Just by watching the wheels, it
SEEMS on this loco, the wheels are quartered, and the center cylinder is powering between the two out side. If you listen to the tone, you get a chuff chuff chuff, pause, chuff chuff chuff...
Meaning an exhaust event at:
0
45(ish)
90
180
225(ish)
270
0
I put the ish because i do understand that with the angle of the center cylinder, it would not be exact. I am no expert on 3 cylinder engines, and with the exception of a shay, this is the first one I have seen.
Casey