Just a clarification, mules (the draft animal) were never used on the Panama Canal. The towing locomotives at the Panama Canal have always been electrically operated. The first set of mules were built by General Electric and were used up until 1964 when they were replaced by "mules" built by Mitsubishi of Japan. The term "mules" was borrowed from the mules that were used most famously on the Erie Canal.
The dimensions refer to the original canal locks, for which the Panamax ships were designed. The updated locks are wider, longer & use water more efficiently and use tugs to guide ships through, rather than the mules the old locks use.
As mentioned below the lock gates are shown facing the wrong way on your "cover picture". They should be "pointing" towards the higher level of water to prevent the water pressure from forcing them open.
The technology is amazing enough. But I am also amazed that even back then they knew that a safer, faster, efficient, and economic passage was gonna have to be built.
Bonus: The Mules & the Water Storage Pools looks OK for now... L.B. In the Future, They may need a Upgrade to do the Job more Efficient... L.B. Security is Priority in the Canal 24/7 for All Workers To Avoid Delays, Strikes & Peace of Mind... L.B. Salutes from Texas... L.B.