The 50/60hz is pretty standard motor stuff. The hz determines the rpm, so 50/60 gets xxxx/xxxx corresponding rpm.
I don't have much 2 speed motor experience, but I have a few machines with Wye start Delta run motors. As I understand it, using the Wye configuration gives an increase in torque and lowers starting current, then switching to Delta makes the motor more efficient at speed.
One of my larger manual machines has a 15HP spindle motor that is wye start, Delta run. When you're setting up the machine you jog the spindle a lot with a jog button that just runs the wye start contactor. I know from setting up the machine on a transformer and troubleshooting when I got it that the starting current is very low for a 15HP motor, like 20 amps. Another wye/delta machine I have is a Blanchard grinder. The Blanchard motor is 50HP @ 705 RPM and has surprised me how little current it takes to spool it up. It draws about 70 amps peak starting load. Some CNC's of mine with 35-80HP spindles are in the hundreds of amps 240V 3 phase during spindle acceleration. One of primary machines has a 35HP 10k rpm Cat50 spindle and when I first powered it up I couldn't run any other machines when it was running. The spindle parameters were set to accelerate from 0 to 10k in a few milliseconds. I changed the parameters to accelerate 10k rpm/.5 seconds and it only draws about 100 amps now which is fine.
Anyways, just rambling about some motor stuff I've found interesting over the years.