Chapter 1.  Epilogue.  We went through the locks on Pacific side... Miraglores and San Miguel. Then next day train ride all the way parallel  - transcontinental - and then actually drove across a “catwalk”.  They are used between ship transits for locals to go from one side of canal to other.   Gatun. And across the actual gate of new locks.  The pic below is looking into the Gatun locks... as Irvin would have seen 75 years ago this past January on transit from New Orleans to Honolulu.