The Building Block Set contains building blocks, a bridge for expanding the Mrklin my world Elevated Railroad. This is the building block set for extending the elevated railroad by four (4) additional Level 1 elevated railroad pillars. The bridge links two elevated railroad pillars and it can be plugged into the adapter blocks. Contents: 32 building blocks for elevated railroad pillars, 4 adapter blocks for mounting track, and a bridge consisting of 3 bridge elements. The building blocks and bridge elements are made of sturdy plastic just right for children