The Evolution Series is a line of diesel locomotives built by GE Transportation Systems, initially designed to meet the U.S. EPA's Tier 2 locomotive emissions standards that took effect in 2005. The first pre-production units were built in 2003. Evolution Series locomotives are equipped with either AC or DC traction motors, depending on the customer's preference. All are powered by the GE GEVO engine.

The ES44AC (Evolution Series, 4,400 hp, AC traction) replaced the AC4400CW model in the General Electric catalogue. These locomotives have been ordered by every Class I railroad in North America.

This dlc features the ES44AC in five Norfolk Southern Heritage liveries.

Included Locomotives:

- NS 8025 Monongahela
- NS 8100 Nickel Plate Road
- NS 8102 Pennsylvania
- NS 8103 Norfolk & Western
- NS 8104 Lehigh Valley

Features:

- animated drivers cabin
- animated wipers
 - animated windows
 - animated rear cabin door
- ACS coupling supported
- functional cabin displays (distance, traction, fuel, brake status, throttle, warning lights for various loco functions and more)
- animated fans
 - custom sound
- custom head and ditchlight
 - crossing light support (30 sec auto bell and ditchlight)
- 3 weathering skins for locomotive and bogies (can be assigned individually)
- dynamic fuel consumption
 - can run out of fuel if you want it (off by default)