The Thomas Dowrick Papers contain biographical materials, documents, including a diagram, pertaining to the whistle valve invented by Dowrick and Chase, their patent on the valve, and the marketing of the invention by Viloco. The papers also contain letters to and from Viloco concerning the whistle valve, and records of royalty payments to Dowrick and Chase.

Thomas Dowrick was born in England in 1890, and after serving an apprenticeship in a shipbuilding firm emigrated to the United States. In 1917 Dowrick went to work for the Southern Pacific at Sacramento as a machinist. He later worked for the Atchison, Topeka & Santa Fe, but returned to the Southern Pacific, eventually becoming a foreman at the Sacramento Shops.

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