EMC AA

{{more footnotes|date=July 2016}}

{{short description|Locomotive class}}

{{Infobox locomotive

| name = EMC AA

| powertype = Diesel-electric

| image =

| caption =Missouri Pacific 7100

| builder =General Motors Corporation (EMC/GM)

| builddate = August 1940

| totalproduction = 1

| aarwheels = A1A-3

| gauge = {{track gauge|ussg}}

| locoweight = {{convert|247340|lb|kg|1|abbr=in}}

| weightondrivers = {{convert|97700|lb|kg|1|abbr=in}}

| fuelcap = {{convert|1200|usgal|abbr=on}}

| primemover = EMC 12-567

| enginetype = V12 diesel

| cylindercount = 12

| maxspeed = {{convert|98|mph|abbr=on}}

| poweroutput = {{convert|1000|hp|kW|sigfig=3|abbr=on|lk=in}}

| tractiveeffort = {{convert|24425|lbf|kN|2|abbr=on}} at {{convert|34|mph|abbr=on}}

| operator = Missouri Pacific Railroad

| fleetnumbers = 7100

| retiredate = 1962

| disposition = Scrapped

}}

AA was a designator used for several different diesel locomotive types custom built by General Motors Corporation EMC/GM with passenger or baggage space in the same body. This locomotive is listed as class AA-6{{cite web| url=http://www.thedieselshop.us/MoPac.HTML| title=Missouri Pacific All-Time Diesel Summary| website=The Diesel Shop| first=R.| last=Craig}} by R. Craig, and the designation is logical as the locomotive is described as "half an E6" in the Second Diesel Spotter's Guide.{{cite book| last=Pinkepank| first=Jerry A.| year=1973| title=The Second Diesel Spotter's Guide| location=Milwaukee, Wisconsin| publisher=Kalmbach Publishing Co.| page=EMD-122| isbn=0-89024-026-4}}

One such was a single locomotive built for the Missouri Pacific Railroad, delivered in August 1940, numbered #7100. MP 7100 was built for service with the Delta Eagle passenger train, which ran between Memphis, Tennessee and Tallulah, Louisiana. Note: Missouri Pacific ordered all their 'E' units with portholes instead of square windows like most of the E series from the EA to E7's. This was the only MoPac unit with square windows (on the baggage door).

Since the two-car train the unit would have to haul was comparatively light, the AA was built with only one 1,000 hp EMD 567 V12 prime mover, and a baggage compartment where the second diesel would have been.

Other EMC/GM locomotives carrying the AA classification include the Pioneer Zephyr, Flying Yankee, and General Pershing Zephyr power units.