It's a little more confusing than that.

Most builders offered at least two horsepower ranges for switchers, but typically they were involved in a horsepower race for road units. Older, lower horsepower, locomotives were downgraded to lower priority service as newer more powerful units were purchased.

At some point, the fancy new high horsepower designs did not meet the railroads needs for secondary service or was something really suitable for shortline or industrial use. Consider GE who most people typically consider beginning production of the U25B about 1959 then adding the U25C, which then developed into the U28B/C, then to the U30/33/36B/C series.

In reality, GE had ended its partnership with Alco and introduced the Universal line in 1956 though primarily aimed at the export market. The line included the U4B and U6B powered by Caterpillar engines, and several designs powered by 6, 8 and 12 cylinder Cooper-Bessemer FW/FV series engines. The only initial production design aimed at the North American market was the UD18 which NdeM got a few. The U25B introduced the FDL-16 which had been initially developed by Cooper-Bessemer before GE bought the FV/FW line of engines from them.

It could be argued that the first Universal designs built were the two 54 ton end-cabs built for US Gypsum, but it may have been that these were special designs developed for USG and then adopted by GE for advertising their new line. The first actual production Universals were the U9C in 1957. So while GE continued to catalog and build a wide horsepower range of locomotives for export use, North America only had the newest and highest horsepower designs.

By comparison, EMD had been forced into turbocharging, so their road locomotive models had split into a roots-blown line and a turbocharged line. The 1800hp GP/SD28 was the roots blown version of the 2500hp GP/SD35. After the change to the 645 engine, the switcher line of SW600/900/1200 became the SW1000/1500. The GP/SD28 line didn't sell very well, but by the late 60s there was an increasing demand for designs to replace WWII and dieselization era locos that were approaching the end of their economic life. So EMD's initial offering was the 8 and 12 cylinder roots blown engines for switchers, and the 16 cylinder in roots blown 2000hp GP/SD38 and 3000hp GP/SD40 as well as the DD40 and SD45. Customer demand led to the 12 cylinder turbocharged GP/SD39, besides a little more hp and fewer cylinders they were more fuel efficient in higher throttles than a roots blown engine.

All the Cooper-Bessemer FW/FV engines that became the GE FDL series were all turbocharged, and GE had a 6 cylinder (replacement engines for 70 tons), V-8, V-12 and V-16 engine line to choose from - resulting in the U18B, U23B/C and U30/33/36B/C line.

You can argue that the U36C was the direct competitor to the SD45, the U30B/C to the GP/SD40, and the U23B/C to the GP/SD39. Where do you put the U33B/C? And where do you put the U18B - as the direct competitor to the GP38 or the GP15-1 since the horsepower doesn't match? And since GE Dash-7 production began a few years after the EMD Dash-2 you either have to break down production by year, or consider the Dash-7 and Dash-2 lines as just upgrades to the Universal and 40 lines.

To accurately compare production, I would consider US purchases of the smaller 4-axle road engine designs - the EMD GP15-1, GP15T, GP38/-2 and GP39/-2 compared to the GE U18B, U23/B23-7 production totals - in which EMD obviously beats GE. EMD was considered to have the better prime mover design, and most roads believed a roots blown EMD was better in low throttle service. On the other hand the GE752 traction motor had a higher rating than the EMD D77, and I believe GE offered a little better price trying to stay in the market.

It is also interesting to consider proposed or cataloged models never built, or what the export market supported. There was a proposal by EMD to build a 6-motor 3600hp loco using a pair of turbocharged 12-567D for SP, but to my knowledge EMD never turbocharged any 567 other than the 16 cylinder GP20, SD24, GP30, GP/SD/DD35. The SD39-2 was cataloged, but there was apparently no interest though the GP39-2 outsold the GP/SD39. There never was a SD39 tunnel motor either, yet the equivalent export model was popular.

GE cataloged an end-cab U18BT, as well as a B/C28-7 which never sold. GE did a fairly brisk business in Caterpillar end cab Universal and predecessor switchers, but only a handful sold in North America. GE did build a narrow gauge SG10B switcher for South Africa using a derated V-8 instead of an I-6 to compete with the EMD SW1002, though some industrials got the same design as a SG15B.

You have to consider the range of comparable designs. Personally I much prefer working on an EMD compared to any domestic Universal or Dash-7 GE. You really can't beat the EMD design of the era. There are those engines you swear by, and those you swear at. And the loco design has to fit the use. I don't imagine Sammie will be buying any B40-8s regardless of price anytime soon.

Bruce Butler Wrote:
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> SP5103 - good point. I never thought about the
> GP39 (or the GP39-2) but as you point out, it is
> more comparable to the U23B than the GP38.
> According to Wikipedia, 23 GP39's were produced
> between 1969-70 And 239 GP39-2's were produced
> between 1974 and 1984. At 481 produced, the U23B
> outsold the 2 GP39 models. Why? Maybe the U23B
> was priced lower.
>
> SP5103 Wrote:
> --------------------------------------------------
> -----
> > One could argue that the U18B and U23B/B23-7
> were
> > both competition for the GP38/GP38-2; but the
> > GP39/GP39-2 is more comparable to a U23B in
> > horsepower (2250 vs. 2300(edit)) and both have 12
> > cylinder turbocharged engines.