03173/74 Sealdah ⇌ Agartala "Kanchanjungha Special" (via Dankuni)
&
03175/76 Sealdah ⇌ Silchar "Kanchanjungha Special" (via Dankuni)
Most probably both Kanchanjungha will change their locomotive at New Jalpaiguri (Electric to Diesel on UP direction...
more... & Diesel to Electric on DN direction)
Source: Uttarbanga Sambad