EMD GP22ECO

{{more citations needed|date=August 2016}}

{{Infobox locomotive

| name=EMD GP22ECO

| powertype=Diesel-electric

| gauge={{track gauge|ussg}}

| builder=Electro-Motive Diesel (EMD)

| poweroutput={{convert|2150|hp|abbr=on|lk=in|sigfig=3}}

| aarwheels=B-B

| uicclass = Bo'Bo'

| cylindercount= V8

| primemover=EMD 8–710G3A–T2

| transmission=Diesel-electric

| image=KCS 2820 Retro Belle.jpg

| caption=KCS #2820 post-rebuild with a "Retro Belle" paint job

}}

The EMD GP22ECO is a {{convert|2150|hp|abbr=on|lk=in|sigfig=3}} B-B diesel-electric locomotive rebuilt by Electro-Motive Diesel and Norfolk Southern's Juniata Shops. Initially EMD built two GP22ECO demonstrators, one based on a GP9 and one based on a GP40,{{cite journal| journal=Trains| title=EMD returns to re-power market| author=David Lustig| date=July 2008| page= 24}} but thus far all orders have been for conversions based on EMD GP40 and EMD GP40-2 series locomotives. The rebuild involves replacing the existing prime mover with an EPA Tier-II-compliant turbocharged V8 710G3A, with Electronic fuel injection. The prime mover is mated to an AR10 alternator for traction power, a CA6 alternator for control power, and a computerized control system. Applying this to a 6-axle locomotive results in a SD22ECO. Some 6-axle locomotives could alternately be converted into a SD32ECO, using a {{convert|3150|hp|abbr=on|lk=in|sigfig=3}} V12 instead.

When applied to GP40 or GP40-2 series locomotives, this conversion does not alter the external appearance of the locomotive, although the conversion of the GP9-based demonstrator required extensive changes to the long hood. The GP22ECO offers customers a 'factory' upgrade of existing locomotives.

Norfolk Southern's units were rebuilt from GP38AC units. They also feature electrical, mechanical, and emissions improvements.