Medium frequency transformers cut energy consumption by increasing efficiency and reducing vehicle mass (all numbers refer to 16 2/3 Hz systems):

Efficiency effect

Efficiency of medium frequency transformers: > 94% (Efficiency of conventional transformers: ~ 92%)

Transformer efficiency (and with it the overall efficiency of power train) increased by 2 – 3%. It is assumed that the same efficiency gain can be obtained for higher power classes as well, e.g. high-speed trains or freight locomotives.

Efficiency gains in 50 Hz systems will be lower. Specific numbers are not available.

Mass effect

DB prototype about 40 – 50% lighter than conventional transformer.

Mass of conventional transformer in this power class: ~ 1 ton. Mass of trains in this power class: ~ 100 tons.

Typical mass reduction: ~ 0.5% of train mass.

	Traction	Brake energy recovery	Effect on train mass	Elasticity with regard to train mass	Effect on total energy consumption for traction
Suburban train	Electric	no	0,5 %	0,64	0,3 %
	(16,7 Hz)	yes	0,5 %	0,57	0,3 %

Mass effects in other power classes are difficult to assess as long as no prototypes exist. The case of suburban trains however shows that the additional effect through mass reduction is small compared to the efficiency effect.

Overall effect

Judging by ongoing R&D, medium frequency transformers may save up to 3 % in main line and up to 4 % in regional line vehicles (in 16 2/3 Hz systems)

Fleet-wide effect

MFT is only applicable to AC traction, and benefits are highest for 16,7 Hz systems. No data are available to determine whether application in 50 Hz systems is reasonable.

Estimated overall energy efficiency potential (in 16,7 Hz systems): 1 – 2 %.