The William A. Box Iron Works Company, formerly the Dillon Box Iron Works Company, was a Denver, CO-based metalwork company founded in 1902 by William A. Box and Frank Dillon, which manufactured electric traveling cranes, mining machinery and railway crossing alarms. They are most notable for their "Denver" electric sirens, which were the first successful electric sirens patented in 1915 that paved the way for the booming fire siren market of the 1920s. Many of these "Denver" sirens can still be found in use today, despite being 90-110 years old.
In 1902, the Dillon Box Iron Works Company was formed in Denver, CO, headed by William A. Box and Frank Dillon. It was found at the time that the numerous steam whistles and fire bells used at the time were confusing, and sought to create a siren that would be noticeably distinct. The company experimented with creating electric sirens in 1905, most of which would prove to be a failure. In 1910, Frank Dillon would leave the company and the company would be renamed to the William A. Box Iron Works Company. Box would find success with the Denver Type-A in 1915, alongside other Denver-branded sirens such as the Duplex and Quadruplex. These would all be patented in 1915.
Unfortunately, William Box would pass away in 1931, ultimately leading to the company shutting down.