Yes indeed. With the exception of class 313s, all modern mainline EMUs have a traction current bus. Class 313s are subject to Northern City Line regs which forbid a unit traction bus (whilst on DC).
But they don't pass traction current between units nowadays. Unit jumpers don't carry traction current !!
Also the 37* series emus have a pickup shoe at each corner of each driving motor (ie, 4 per vehicle), which helps reduce gapping/arcing.
And all 3rd rail units jerk and arc like crazy in the snow - same as they ever did.
Best wishes,
FP