The Minecart Type Rail is added by Expanded Industry to offer additional levels of Minecart detection.
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Configuring the Minecart-Type Detector Rail Edit

The rail is configured by placing a sign either 1 block above it or 2 blocks below it and indicating the desired type and output.  Both signs may be used for up to 8 different detections.  In the case of multiple minecarts being in the detection area, the highest value matched is output.

The syntax is simple: [name of cart]=[value] or [name of cart]:[value]

The name is a simple match with the end of the item name (case insensitive), e.g. "Furnace" will match "Minecart with Furnace".  This should work for all vanilla carts, mod-added carts, and localization.

Additionally "Empty" will match an empty minecart, and "Command" will match the command block minecart.