"Royal engine" of the Bombay, Baroda, and Central India Railway. D or D1 class 4-4-0 locomotive of BBCIR. Ten locomotives of D1 class (No. 241-50 built by Bayer Peacock in 1905-6) were named after British royal prince or princesses, and that may be why the caption on this photograph designates it a "royal" engine. From "Railway and locomotive engineering : a practical journal of railway motive power and rolling stock" (1900s) Scan from the Internet Archive of Book Images.