A duo-locomotive from GE?

In Scandinavia many operators use an electric- and an idling diesel-loco in the same train. The diesel is for workings in both ends of the jurney.
What is needed is a 6-axle loco with at least a 1 MW diesel and an about 6 MW transformer (15 kV 16 2/3 Hz and maybe also 25 kV 50 Hz) for feding the traction motors. Weight 135 metric tons (150 american tons) and with aditional weight 150 metric tons (166 american tons).

Working diesels under catenary have a penalty surcharge from the trackowner.
Bombardier have a 4-axle Traxx with a very small diesel just for about 1 km workings. But a 6-axle engine is needed and probably the best way is to make a duo-loco from a diesel fitted with a small engine an a transformer.

Anyhow, someone is going to make a real freight duo-loco.

GE built several dual power passenger locomotives for Amtrak and Metro North. GE started out in about 1930 with the "tri-power" locomotive for the New York Central. The tri - power refers to diesel - third rail electric - battery power. Its intended use was for operation in city street switching operations which in that time was a low smoke regulated are. Since then not used in freight service. Except for passenger applications operation in tunnels there isn't anywhere that it would be worth while here in North America. NJ Transit is now buying the ALP45DP from Europe for use under catenary.