and engineer pants pants have bibs too, but they would almost always be called 'osgoshes' after the clothing company in Oshkosh, (in Wisconson? or is it Indiana?) Osgosh made overalls in a heavy striped cloth, (that looked like pillow ticking of old)-- somehow, osgosh became associated with RR engineers, almost exclusively.

Oshkosh, by gosh!, offered small overalls for kids, with matching caps, and wooden whistles that sounded like RR whistles. (i suspect if you looked up Oshkosh.com, you find them for sale on the web site.) easily, 50% of the boys in US have had a pair of Oshkosh overalls, at least once in their lives-- they got them the same year they got the toy train set for christmas..
(edited, since i had osgosh, not oshkosh..and the web site does still sell the overalls)