All of the Geeps covered in last week's profiles have been reproduced many times over. You'd think there was no more room for more models of these classic engines - but you'd be wrong. Athearn has stepped up the bar and produced the finest versions of the GP7 and GP9 ever. While railfans griped that these new diesels "all looked alike" - especially compared to the steam locomotives they replaced - there were variations from railroad to railroad.

Athearn's latest model of the GP9 includes roadnumber-specific detailing!
©2013 Ryan C Kunkle, licensed to About.com, Inc.

Those detail changes only got more intense as the locomotive's aged and were modified. Athearn has not only taken the time to reproduce the differences from road to road, but even from locomotive to locomotive! Nowhere can this be more seen than in later models like the Conrail units reviewed here. Of the four numbers Athearn chose, one was originally a New Haven engine, one Pennsylvania and two New York Central. That creates differences in horns, mu hoses, dynamic brakes, air filters radiator fans... the sort of variations that once required hours of research, cutting, drilling and detailing to recreate.

This road number-specific detailing has become a staple of Athearn's Genesis locomotives in recent years. It is taking the hobby to a whole new level of realism. These models are perfect for the perfectionists in the hobby - but priced reasonably enough for anyone to enjoy. Just don't wait - these limited runs don't sit on shelves very long! Read more in my complete review.

Let's wrap up our week of early GM "Geeps" with one that was the most stylish if not the most successful.

The GP30 was unveiled in 1961 in another hurried attempt to keep up with the competition from Alco and now GE as they introduced more powerful locomotives. EMD pushed its existing diesel engine to the limit and introduced several other design refinements (30 according to the sales team - hence the locomotive's designation.) But perhaps most noticeable was the addition of a large "hump" on the roof of the locomotive to accommodate the new air intakes. This gave the GP30 a unique look that made them instantly recognizable from all predecessors and followers. In an era when most "Geeps" looked remarkably the same, this was a welcome change for railfans at trackside.

The styling has made the locomotive popular on model railroads as well. Unfortunately for EMD, mechanical problems coupled with the quick introduction of the more powerful and reliable GP35 kept the GP30's sales low and also their time in the spotlight short. Many found early retirement, others however were rebuilt and still run today, making the GP30 a good choice for many modelers looking for a unique locomotive to add to their roster. Learn more in this locomotive profile.

Despite the successes of EMD's first Geeps, by the middle of the 1950s, the company again found itself slipping behind as the competition raced to build larger, more powerful locomotives. EMD's answer to those designs in a four-axle locomotive was the GP20. This was the first Geep with a turbocharged engine, producing 2000 horsepower.

The locomotive was not nearly the sales success that its predecessors had been, but it did pave the way for future designs. It was also the first "Geep" that really wasn't General Purpose. None of the locomotives produced were equipped for passenger service and the turbocharged engine was really most tailored to high-speed freight runs.

Although far less prevalent than other Geeps, the GP20's role in history and presence on railroads all across the country make it a good candidate for many layouts set in the late 1950s to the early 2000s. Read more on in this new locomotive profile.

The GP7 proved that EMD would finally be a contender in the road-switcher market. The popular locomotive found homes on railroads large and small all across North America.

Externally, the GP9 was nearly identical to the GP7 - and its effect on railroading was equally as impressive.
©2013 Ryan C Kunkle, licensed to About.com, Inc.

When EMD upgraded the locomotive to 1750 horsepower as the GP9 in 1954, the results were even more impressive. While the process of replacing steam with diesels had begun nearly two decades earlier, the GP9 would be responsible for dropping the fires on many railroads for the last time. Even long-time hold out Norfolk and Western ordered more than 200 of the undeniably practical and essential Geep.

Like the GP7, the careers of most of these Geeps lasted well beyond the transition era. The locomotives were rebuilt in large numbers in the 1970s and 1980s. Many could still be found on Class 1 railroads into the 1990s. Even more were sold to shortlines, industries or preserved in museums. Dozens remain in operation today - long after watching younger diesels go the way of the steam locomotives before.

With more than 4100 roaming the rails, the GP9 deserves a home on almost any model railroad. Fortunately, they've been produced in high numbers in every major scale as well. Learn more in this new locomotive profile.