Early Boston and Providence railway locomotive

Yankees Under Steam,  Edited by Austin N Stevens, Yankee Inc. 1970

In the 1970 book Yankees Under Steam, according to a story, Whistlers Father by H. F. Thomas, this steam locomotive, designed by Whistler's father- George Washington Whistler- and belonging to the Boston and Providence Railway is labelled the Bristol and is claimed to be the first locomotive ever to be photographed (in 1840).
No denying that this is an old photograph (daguerrotype, actually) of a very early locomotive, and I can't quite make out the name on the driver fender.  However other references refer to the Bristol as being one of four American class 4-4-0 steamers built in 1846.
The railway had an earlier locomotive named "Boston" and another named "Taunton" either of which could be imagined to fit the fender lettering. The cab is unusual for the time. In the book below there is reference to a jury-rigged cab applied to one unnamed locomotive.
"In 1843, a Boston and Providence employe named John Davenport, perhaps an engineer tired of
being blasted by wind at speed and pelted by rain, sleet, snow and burning embers from the engine‟s
smokestack, rigged up a cab on a locomotive. Officials, however, frowned on the idea, claiming that
engine crews would become loafers if they had such a comfortable place to work, and scoffed, "Next thing we'll be giving them something to sit down on, too." But after a trial period, the brass collars
found in favor of this radical departure. "

The definitive history of the Boston and Providence Railway here.