The new Narita Express train, NEX E259, is due to start service on Oct 1, 2009. When I got off the Yamanote train at Shinagawa station yesterday, I saw them practising the coupling of the train.
When the train is in operation the two parts of the service, one coming from Yokohama and the other coming from Shinjuku, get joined up at Tokyo station.
I took some video of the coupling practice session. Not sure how many times a day they practice this, but I bet they cant wait for Oct 1 to roll around.
Here is the first section where the train comes into the platform.
after stopping for a short while, the train then moves forward the remaining few feet to dock with the other carriages before leaving for the airport.
There were quite a few people snapping photos at the station. The front section of the train makes quite an impact.