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An Amazing Number

The picture above shows the International Bridge between Fort Erie, Ontario, and Buffalo, New York. It’s a wrought-iron Pratt through-truss bridge constructed in 1873 and still in use for its original purpose of carrying trains.

The bridge is in three sections: a series of truss spans across the main channel of the Niagara River, a causeway across Unity Island, and a smaller series of spans across Black Rock Channel from the island to the US-side mainland. (Note that the name “Unity Island” is less than a decade old. The former name of the island is an ethnic and gendered slur that I won’t be using.) The long section across the main channel is a single track and had a swing span, but that has not moved in something like 80 years. The short section across Black Rock channel was built with two tracks, one of which has been replaced by a road to serve local traffic to the island; the swing span on that side is still in use. The land span across the island was built as a wood trestle and replaced by an earth embankment, which seems to be a theme.

The description includes the sentence: “The iron for the bridge was manufactured at Phoenixville, Pennsylvania.” That certainly implies that the fabrication was at the Phoenix Iron Works, which was by far the largest industry in that small town. If it was, they were serving solely as a manufacturer, since the bridge, as seen above, uses ordinary built-up box members for compression, rather than the patented Phoenix column, a riveted built-up hollow circular section.

This is all fairly normal except for the pleasant surprise that the bridge is still in use. One statistic that jumped out at me is that, supposedly, 264 trains crossed the bridge on July 10, 1916. That’s eleven trains per hour, or a train every five and a half minutes, over a bridge with a single track for most of its length. That’s an average, assuming that the trains were evenly spread through the day. It’s possible, although it would require a lot of careful coordination. I suspect that a fair number of those trains may have been quite short, maybe even single locomotives deadheading back to the yards on either end. An average headway of less than six minutes looks pretty good compared to most mass-transit systems we have today, but this was passenger and freight heavy rail.

It’s also possible that this statistic is a mistake. The fact that 264 is exactly 24 times 11 makes me suspicious. Maybe the peak was eleven trains in an hour on a busy day and that got garbled into eleven per hour for the whole day? Another mystery that I’ll never know the answer to.