Locomotive Descriptions and Phases - GE U18B, U23B, U30B, U33B, U36B

The GE Universal series entered production in 1956, with the first road switcher, the U25B, introduced in 1959. By the late 1960s and early 1970s, several models were available that all followed a common design, with only a few differences to account for varying engine sizes and frame lengths.

The U30B started production in 1966 as an evolution of the previous U28B, initially sharing the same carbody. A slightly more powerful model, the U33B, was introduced shortly afterward, incorporating wider radiators and a redesigned rear hood section (the latter of which was adopted for the U30B at the same time). All three models, along with the earlier U25B, were powered by a 16-cylinder FDL engine. However, unlike with previous horsepower increases, the U30B was not discontinued when the U33B was released. In 1968, GE introduced the U23B, a 12-cylinder, medium-horsepower variant that proved to be the most popular 4-axle model of the series; it was distinguished by six (rather than eight) tall engine-room doors per side. In 1970, the U33B was uprated and replaced by the U36B, and with the increase in horsepower provided by the FDL engine, the 8-cylinder U18B was added in 1973.

Four of the five models were 60' 2" long with 36' 2" truck centers; the U18B was 5' 6" shorter. Concurrent six-axle Universal models were longer but visually very similar, with a nearly identical hood with 7 feet of mostly blank space behind the cab.

GE made many gradual improvements to the Universal series during production, which were generally applied concurrently to all models. Many of these changes were not evident externally; for instance, GE made many improvements to the FDL engine and electrical system as horsepower was increased and reliability improved. However, some changes, such as wheelslip control, were readily visible. GE's early wheelslip-control system relied on axle alternators on every axle, which are present on most earlier Universal units. Later systems measured current-draw differences between the traction motors, eliminating the need for all but one axle alternator. Depending on railroad specifications, some later-production Universal units continued to use both systems.

Earlier-production units used oil-bath air filters, evident externally by a high-mounted intake below the front of the radiators starting with Phase 2a. Most Phase 2b1 and later units used paper air filters, which used a low-mounted intake (the same doors and intake flipped vertically).

Several changes in the early 1970's were the result of increasing standards or regulations. Footboards were forbidden on new locomotives starting in early 1975, and Universal locomotives were built without them starting in late 1974. Shortly afterward, GE widened the corner steps and raised the coupler cut levers to make them accessible from the steps. The external headlight and numberboard access panels at the very end of Universal production coincided with AAR Clean Cab concepts, where corners and hard edges inside the cab were minimized.

In 1977, a combination of significant updates led to the creation of the "1977 Series" or Dash-7 series of locomotives, and the U23B, U30B and U36B were respectively replaced by the B23-7, B30-7 and B36-7.

Phases

I've based these phases on the U30B roster compiled by David Thompson. However, I've found a few minor errors and a number of additional detail differences, so I've made the following changes:

• I've added Phases 2b2 and 2b3 as sub-phases of Thompson's Phase 2b, describing additional detail variations affecting the left-side equipment boxes and handrail stanchion spacing. These details changed in a slightly different order on six-axle Universal units.
• Thompson defined Phase 2d by the disappearance of the drip rail on the radiators. However, this detail was inconsistent up to the end of Phase 2e. I've labelled units as Phase 2d when they have no drip rail but still have the built-up pilot area of Phase 2c.
• I've removed the original Phase 2f2 and 2g2 (same as 2f and 2g but with square door latches) since they did not apply to four-axle U-boats. However, I have still divided Phase 2g due to differences in the doors behind the cab.
• Due to additional changes in the steps, pilots and handrails, I've added Phases 2h2 and 2h3 as sub-phases of Thompson's Phase 2h1, with the original 2h2 becoming 2h4.

Only the U30B spanned all phases; the other four models were all Phase 2a or later.

Six-axle models underwent a very similar (but not identical) series of evolutions; see GE U23C, U30C, U33C, U36C Phases.

Notes

1. Pilots, Phase 2h2: Double cut levers with no footboards appeared on some earlier units, such as SOU Phase 2g U23B's.

References

Davis, W. (2010). Wheel slip control in the General Electric Universal Series. Retrieved December 2018 from http://railroadlocomotives.blogspot.com/2010/12/general-electric-wheel-slip-u25-u36.html

Davis, W. (2014). General Electric's 1977 Series Locomotives. Retrieved December 2018 from http://railroadlocomotives.blogspot.com/2014/01/general-electrics-1977-series.html

General Electric. Educational Manual, Model U33 Diesel-electric Locomotive. GEJ-3866, 1969-07.

General Electric. Operating Manual, General-Electric Diesel-Electric Locomotive. GEJ-3856B, 1972-06.

Heacock, D. J. (2012).GE U36B LOCOMOTIVES. Retrieved December 2019 from http://www.trainweb.org/csxphotos/model_U36B.htm

Sarberenyi, R. GE's U18B - Original Owners. Retrieved November 2018 from http://www.trainweb.org/jaydeet/u18b.htm

Sarberenyi, R. GE's U23B - Original Owners. Retrieved November 2018 from http://www.trainweb.org/jaydeet/u23b.htm

Sarberenyi, R. GE's U33B - Original Owners. Retrieved November 2018 from http://www.trainweb.org/jaydeet/u33b.htm

Sarberenyi, R. GE's U36B - Original Owners. Retrieved November 2018 from http://www.trainweb.org/jaydeet/u36b.htm

Thompson, D. GE's U30B - Original Owners. Retrieved November 2018 from http://www.trainweb.org/jaydeet/u30b.htm