Glad Marc posted this:
also try use the jumper cable to start up large diesel engine also you can see the jumper cable do move
I once saw the very same thing occur - with of all things, the jump starting of one Diesel Electric Locomotive from another Diesel Electric Locomotive (this was at a Branch Line's Station where Locos are kept, fueled and light maintenence performed for equipment used as local switch duties).
The unit being "jumped" (an SW1500) was hard starting, which nearly drained the Batteries; so a running, warmed up unit (GP9) was used to jump start the switcher unit (the SW1500).
The cables bounced quite hard during locked rotor through the first few rotations of the Crankshaft, then they bounced accordingly as the "tighter" pistons / cylinders were moving up on compression.
Being that these Prime Movers are 2-stroke Diesels with Blowers (Superchargers) and Turbochargers, the cranking compression is lower, and compression increases when things move faster; - i.e. the scavanging devices kick in; but still has a large volume of air to squeeze into a small space during starting.
Wierdest stuff to see (and of course- no camera!). Jump Starting a Locomotive was, in lieu of a better word; "Odd Enough", but the reactions of the cables added more "!@#$%" and
to that Day's event!
p.s. since Marc has/does Engineer Locomotives (operates them), I suspect the scenario above is where His reply is targeted towards.
Also, as Scott ("Bjarney") replied, hard starting / large Motor starting does unique things to stationary Conductors - and their reactions are heard with a very "Distinctful Sound" when the Conductors are in Conduit.
Hydro-Pneumatic Plunger type Elevators (actually their Pump Motors) normally set things in motion when they are thrown across the line (started / turned on / begin doing something Kinetic, rather than occupying space and their Rotor has 100% Static Inertia situation...).
Conduits, Boxes, Strapping, Conductors - along with Panelboards, bussing and OCPD belch out a harsh "Buzz/Shake" for about 100-250 milli seconds.