Unable to transport villagers through a portal in a minecart, this was done using coal rails and powered rails. When the track met the portal, the minecart simply fell off down the quarter of a block to sit on the portal. The villager in a minecart just sat in the portal for quite some time, without any effect.
The portal frame is sunken into the ground by one block so that the portal is level with the ground. The minecarts were propelled into the portal using a furnace in a minecart, and this was attempted with purple and brown shirted villagers.
This is a duplicate of MC-67.