On 02.04.17 22:26, John Levine wrote:
Speaking of peculiar, London has four places where trains switch between
overhead and third rail, namely Acton Central, Mitre Bridge, Drayton
Park and Farringdon/City Thameslink. I have no idea how common
pan-up-pan-down in service is globally. The 313 trains at Drayton Park
very noticeably go though a "turn-it-off-and-turn-it-back-on-again" moment.

I don't think it's that rare. In the US, the New York MTA New Haven
line commuter rail switches at Mt Vernon

They raise the pantographs when travelling east.

Changeover was just after the junction at Woodlawn (CP 112), where the
New Haven Line diverged from the Harlem Line, but they moved further
east to the Mt. Vernon-Pelham border in 1993.

This resulted in a small part of the New Haven Line becoming 3rd rail
territory.

There was consensus that they should have left the changeover just north
of Woodlawn as part of that line goes through a cut, thus making track
maintenance and power maintenance more difficult.

and the Boston MBTA transit
blue line switches near Logan Airport.

I think that changeover on the T happens when the train is berthed at
the station, whereas trains on the New Haven do it on the fly.

For added confusion, Penn Station in New York has both third rail and
OHLE, on different services but sometimes on the same tracks.

Yes, but 3rd rail at Penn is all overriding, whereas Metro-North has
only underriding.

There is a direct connection from the New Haven line into Penn via the
Harlem River Branch, which diverges just west of New Rochelle station.
Amtrak trains are now the only trains to run over that line, though the
MTA would eventually like to see New Haven trains running along it.
One of the potential difficulties for this prospect is that M-2 and M-8
EMU trains have only underriding shoes.

Having said that, the MTA have been discussing the prospect of New Haven
Line trains running down the Harlem River Branch for at least 25 years
-- if not longer.

I sometimes think that it is just talk and that this is not likely to
happen.