Hello bubu, welcome to IRI.
Single Diesel BG = Single line Broad Gauge track and no electrification (Only Diesel locos can ply on this route)
Double Diesel BG = Double line Broad Gauge track and no electrification (Only Diesel locos can ply on this route)
Single Electrified BG = Single line Broad Gauge track with electrification (Diesel and Electric locos can ply on this...
more... route)
Double Electrified BG = Double line Broad Gauge track with electrification (Diesel and Electric locos can ply on this route)