...it all depends...

EMC to your EMD-GM to your EMDiesel...the Prime Mover,
is the prime-mover.
The History of EMD is all about a V-type 2-cycle Roots-blown or turbo-charged Diesel engine.
Thousands of families lived off the success of this engine.
Though EMD product usually cost more initially than the competitors, the unitized construction of the products that used this prime mover made them competitive & a Global network of parts distribution and service.
Caterpillar engines litter the History of locomotive production & rebuild-refitting, but the economics of operations precluded that Caterpillar engines were "overbuilt," for the ops of railroading.
The Electro-Motive Diesel as you know it, surrounds the production of the current winner(Series 710V), but does not exclude the 265H engine, that is currently being applied to an order from China. The 265H engine incorporated European engineering & is in fact built for locomotive service.
The applications along with rail locomotives include marine, oil-field & rig & power generation. These customers also chose EMD prime movers for a reason, and loyalty to the brand is important even today. EPA certification for EMD is registered, the engineering changes are going to the floor for production. The new V8 & V12 Eco R&R packages are tailor fitted for modernizing past production applications.
Merely writing-off EMD because Caterpillar builds fine engines is way short sighted. Cummins Engine Co. is aggressive & successfully competitive with Caterpillar, overtaking the Class-8 truck market simply due to EPA certification problems. All Cummins Engines are EPA-Cert at least to Tier-III.
General Electric is also plagued with problems with the next emission-certifications to be applied...let alone the turbo problems that caused a massive recall of the Evolution Series production...that, however brief loss of available motive power will not be forgotten by the Class-1's.
Whatever Caterpillar & Progress Rail decides to do with EMD-built engines, made exclusively in-house in LaGrange, IL, US-America, will be the future for EMD.