Working-class clothing in the 1840s

I'm looking for historical clothing from the 1840s and 50s. The problem is, that's the middle of the Victorian era, so every place I look is talking about waistcoats and frock-coats and top hats; however, the character I'm designing for is an engineer. Nobody works on a steam engine in a frock-coat and top hat! What did working-class people wear? Specifically either the US or Britain, either would be appropriate for my setting (hired by a British investor, working in the west coast USA, haven't decided country of origin).

have you looked up pictures of the era?

I am guessing:
pants of cheap material, likely wool.
A shirt of some kind, likely wool or linen. nothing fancy.
A coat. not the fancy kind, but just a jacket.

of course, a hat a must.

I am thinking that 'My fair Lady' or 'Pygmalion' is a vaguely accurate depiction. You know, the fatehr before he gets the money, or the street people in the beginning.

working class californian 1849
http://commons.wikimedia.org/wiki/File:Gullgraver_1850_California.jpg

railroad workers
http://commons.wikimedia.org/w/index.php?title=File:Engine_-_thrown_over_embankment,_showing_manner_of_raising_it_to_the_track._-_NARA_-_525176.tif&page=1

http://commons.wikimedia.org/wiki/File:ACW_RR_handcar.jpg

folks in the American South in, 1860 and 1870's
http://commons.wikimedia.org/wiki/File:Brownlow-haun-execution-1861.jpg
http://commons.wikimedia.org/wiki/File:Georgia_crackers_1873.jpg

you might find a treasure trove if you can figure out the right language formulation in Wikimedia

some places to start the led me eventually to the above:

Category:Railroads of the American Civil War
Category:London in the 1840's