In the 1870s Harpers had fence contracts in India and where fences led, bridges followed. John Harper would have sent out the cast iron components cables and hangers, while the commissioner supplied the abutments, anchorages, the timber masts and the deck. The timber elements would have rotted away after a few decades and so none of John Harpers bridges survive.
The bridges of Louis had steel lattice masts and a few survived for several decades. However, as far as is known, none is still in use. We have illustrations of three – Jaidhari, Baroda and another at an unidentified location 'near Bombay', now Mumbai. This mystery bridge was erected in 1896 by Arthur Hoare of John Fleming & Co, Bombay. Following that at least three were erected and we know of two - Jaidhari and Baroda (Valdorada). These were erected in 1898 by Turner, Hoare & Co. The bridges appear to bear the name of the erector rather than Louis Harper. It is highly likely that more were erected.
Bridges in India