I was consulting a copy of The Second Diesel Spotter's Guide, to explain the wheel arrangements of certain locomotives, to hopefully a new railfan. I came upon an odd picture of what appeared to be an EMD loco with an A1A-3 configuration and could not show my granddaughter an example of this wheel arrangement.
Can anyone give me a example of this type?
cessna 310I was consulting a copy of The Second Diesel Spotter's Guide, to explain the wheel arrangements of certain locomotives, to hopefully a new railfan. I came upon an odd picture of what appeared to be an EMD loco with an A1A-3 configuration and could not show my granddaughter an example of this wheel arrangement. Can anyone give me a example of this type?
An A1A-3 is basically a motor car: it has one standard "Blomberg" truck in the front, and an unpowered three-axle truck in the rear. Only two traction motors; correspondingly low (switcher-size) diesel engine power (1000hp or less). The back end (where a second engine in a contemporary 'passenger locomotive' would be) is usually set up as a baggage car or 'non-revenue-passenger-carrying' space, unlike the situation in a typical EMD gas-electric car. To my knowledge, none was ever used as RPO space (Seaboard had a couple of motor-trains-on-steroids that had them).
The 'famous' version of this was Missouri Pacific AA 7100 (from 1940). We had a thread about this in 2017. Here's a later picture:
https://nebula.wsimg.com/935639dadc92413ab3366f02cc4b7e12?AccessKeyId=5CF08DE3AA6646FE752D&disposition=0&alloworigin=1
The AB6 used for the Rock Island Colorado Springs connection was originally built this way, too, but acquired a second engine and power truck to make it the equivalent of a full E6B.
There were other motorcars set up with this or similar wheel arrangement, I believe including a couple on Milwaukee with FM opposed-piston diesel engines and C&NW Baldwin 5000A. See also CB&Q 9908, which has an A-1-A power truck but only a two-axle truck in back.
cessna 310The picture in the guide was of an E unit silhouette.
Likely an intentional piece of design 'marketing' -- the passengers would think the train had a full 'streamlined locomotive' on the front (together with the new Budd cars) rather than it being a cheaper 'motor train' approach.
The orignial AB6 was scaled to a particular size for the Colorado Springs connection. When that increased enough to justify more power, the very logical thing was to install the equipment for a full E6 mechanically, and use either a full baggage car or combine.
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