Question: Date station name changed from Burson to Helisma

From: "Salvatore Manna" dharmadog@earthlink.net

I live in a small Calaveras County, California town called Burson. It was founded when the San Joaquin & Sierra Nevada railroad built a station here in 1884. By 1888, the Southern Pacific had purchased the narrow gauge line and in 1904 converted it to standard gauge. At some point--believed to be between 1888 and 1912--the railroad changed the name of the station from Burson to Helisma. Where can I access, or have someone access for me, a series of annual railroad maps or timetables, for example, that could pinpoint the year of the name change? I have scoured the Internet, any book I could lay my hands on, County archives, etc. – I'm a professional journalist – but have yet to find an answer. HELP!

Cheers,

Sal