What is "tram plate"

Tram \Tram\, n. [Prov. E. tram a coal wagon, the shaft of a cart or carriage, a beam or bar; probably of Scand, origin; cf. OSw. tr[*a]m, trum, a beam, OD. drom, Prov. & OHG. tram.]

1. A four-wheeled truck running on rails, and used in a mine, as for carrying coal or ore.

2. The shaft of a cart. [Prov. Eng.]
   --De Quincey.

3. One of the rails of a tramway.

4. A car on a horse railroad. [Eng.]

   Tram car, a car made to run on a tramway, especially a street railway car.

   Tram plate, a flat piece of iron laid down as a rail.

   Tram pot (Milling), the step and support for the lower end of the spindle of a millstone.