JR East Nagano Division this month has run specials (rinji ressha w/ unreserved seating) using 115 series in original Shonan and Yokosuka colors coupled with a kumoyuni mail/parcels railcar, simulating a JNR-era long distance suburban/local service. Locations in this video include the Ooito Line, and the Shinonoi Line, the last scenes being the switch back at Obasute.
Some other shorties:
Official announcement (see page 8):
http://www.jreast.co.jp/nagano/pdf/140523-2.pdf