The lock chambers -steps- are 33.53 meters wide by 304.8 meters long. The maximum dimensions of ships that can transit the Canal are: 32.3 meters in beam; draft -their depth reach- 12 meters in Tropical Fresh Water; and 294.1 meters long (depending on the type of ship).
NEW: The expanded canal will keep its present sets of locks unchanged. In addition, a new set is being built for vessels as large as 366 meters in length, 49 meters in beam and 15.2 meters in draft at tropical freshwater (TFW). These dimensions most probably will define a New-Panamax type vessel.
A conceptual unauthorized video of the new locks may be seen in YouTube New Post-Panamax locks at the Panama Canal