With the Trixbrix Train Tracks adapter you can connect the older type of rails to the current new tracks.
This will work with LEGO® 150, 151, 154, 155, 156, 157 and 159 with the currently sold by LEGO® 7499, 7895, 7896, 7938, 7897, 8867, 60050, 60051 and 60052 among many others
See also:
Straight Rail Set 10x
Narrow Rails Adapter