Load Testing - of a bridge, by lots of trains!

Finally, an opportunity to combine software performance engineering with trains in a way that's not too far-fetched! I attended the exhibit of "fit to print" at the National Library of Australia yesterday (lots of prints from glass-plate negatives from early Australian photojournalism). The above photo (sorry about the quality, it's a photo of a photo), shows load testing of Sydney Harbour Bridge before it was opened with 95 trains. According to https://collection.powerhouse.com.au/object/365369 they were de-commissioned locomotives and load tested the bridge to 27% OVER the design loading - I wonder what they would have done if the bridge started to fail?! Here's a better-quality photo from the above link. Software load testing is often done with specialised benchmarks to ensure they can produce the expected (or more than expected) loads, model different workloads, and capture, analyse and visualise the results, and these days often run on cloud infrastructure to ensure scalability and cost-efficiency; and modelling is sometimes a better way of predicting the maximum capacity of a system and increased latencies. I guess back in those days (no computers - just paper and pencils) this was a pretty impressive demonstration that the bridge would hold up for the official opening!