We took a day trip to the Falls last Friday, and this time we visited the Niagara Parks Power Station which we missed on our last visit. This station was built in 1905, was in operation for 100 years, and now hosts displays about the development of the station itself and hydroelectricity in general.
When in operation, this station had 11 generators running at 250 RPM to produce 25Hz power. This frequency has been obsolete in North America for decades (we use 60Hz), but local industrial customers were still using it.
You can also take the elevator to the bottom of the pit and walk along the tunnel which use to drain the turbine outfeed to the Niagara River downstream from the falls. The tunnel is well-lit, large (considerably bigger than a train tunnel), cool (refreshing on a hot day) and very humid. At the end of the tunnel there is a viewing platform in the gorge where you can see the Falls and, depending on the wind, get soaked by the mist. Rain ponchos are available free right by the tunnel exit. On the elevator trips you can see the turbine, drive shaft, and penstock for the adjacent generator (I think it was the #2 unit) through the gloom.
We all felt this was a worthwhile stop. It may seem a bit expensive at first, but by Niagara Falls attraction standards it is actually a good deal.