Horizontally-mounted antennas on Metro-North

Does anyone have any infomation on the types and model of antennas used on the Metro North trains running along the New Haven line? I thought I seen some horizontally mounted antennas, that emit a vertically polarized signal pattern. If you have any diagrams or schematics it would be very helpful also.

The antenna's used are Sinclair antenna's

yeh, not sure if that is what you mean, but a horizontally mounted antenna, 1/4 wave long travelling just above a ground plane, when terminated, is a travelling wave antenna and does indeed generate a vertically polarized signal .. sumpin most people dont believe... Ed