switch machine control

[tankist]

looking at options of controlling those peco switch machines and came across this
http://home.cogeco.ca/~rpaisley4/ToggleTwin.html

i really like the idea of relegating the high currents from toggle switches to semiconductor components so i looked at his transistor controlled circuit.

i majored in electronics during high school but its been some time now. can anyone please explain what is going on here? i understand that as soon as that darlington opens, capacitor discharges through the coil, but then what? the switch is on-on DPDT meaning as soon as it is thrown it stays there. so how does the darlington close??? what am i missing .

EDIT: hmmm, as soon as that cap depletes the current through the coil is only 20mA which i guess is enough to only heat the ~3ohm coil lightly as most voltage wil drop across the 1k resistor. but something still seems strange here.
opinions on this circuit?

thanks

 

[theSnowman]

It appears it will work well, if not a bit slow(? recharge times)
With the switch in it's present position, current will flow through r2, the switch machine coil A and q1. It will also flow through r3, charging up c2.
Throw the switch and c2 discharges across coil B and through q2 while current stops flowing through q1, and instead into c1 charging it for the next flip.
I am not sure how long it takes to charge the caps, and lowering r2 and r3 should keep in mind continuous current flow through the coils.
I am simply a hack at electronics, albiet for decades...so it is how I see it and not how an engineer sees it...
keith