Hey Guys
No reason to not have a multimeter or two on hand. I have three of the below meters. The AC voltage reading compares very closely to the reading on my digital Oscilloscope.
http://www.harborfreight.com/cpi/ctaf/Category.taf?categoryid=551&pricetype=S&categoryname=Electrical%20Test%20Equipment
You cannot read AC current with this meter but for general model railroading use, that is not an issue.
Rich