Railroad symbol

[Camden Daily]

Does anyone have a good symbol or set of symbols that they use to draw
railroads?  I'd like the basic two parallel lines with horizontal
'ties'.  I just can't seem to get it to work right.

Otherwise, does anyone have any in-depth documentation for how to draw
symbols?  The documentation out there seems to be more a set of
examples rather than an explanation of how mapserver actually
interprets the data.

-Camden Daily