Tubal Cain Engines
Tom D. Walshaw (1912–1998) was an engineer, author and contributor to the British magazine Model Engineer. Most of his magazine contributions and books were written under the pseudonym "Tubal Cain". The pseudonym refers to the biblical metal worker. He wrote two books on making simple model steam engines. Many successful engines have been built using the designs in these books.
Sadly I have neither the facilities nor the skills to scratch build my own engines, but examples of Tubal Cain engines can sometimes be found for sale.