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| In May 1966, the first experimental General Electric AC/DC transmission locomotives appeared, along with new direct current locomotives of model U28 which utilized the same body. General Electric had seen its lead in unit horsepower, which was slim to begin with, erased by both ALCO and by Electro-Motive, and had worked diligently to increase locomotive horsepower. During the year 1965, numerous test units nominally classed as U25B or U25C were supplied to the railroads as parts of a test program in which these test units operated at a higher rating, either 2750 or 2800 HP for traction. These units incorporated a modified engine, which among other things contained a new single pipe exhaust manifold. General Electric released the first of the U28 locomotives, in four and six axles, at the beginning of 1966. Five months later, the real endpoint of this work appeared with the test U30 units. Again, during the one year production of the U28, some units were mixed in rated 3000 HP and equipped with AC/DC transmission. |
| The advertisement at left dates from late 1965, and clearly shows the new equipment layout which entered production in May, 1966. The model numbers are not mentioned; the units are simply referred to as the "new 1966 locomotives." This design was used on the U28 for the rest of the period, and on the following AC/DC U30. No 2800 HP units used alternators. |
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| Above, air system of the U30 showing equipment blower location behind cab. |
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| General Electric FDL-16D engine with single pipe exhaust manifold and steel cylinder heads. The FDL engine used unitized cylinder assembles without conventional cylinder heads (that could be unbolted and removed from the top.) However, the U28 and U30 units used a steel insert, or cylinder head, bolted into the top of the unitized assembly, which contained passage for fuel injection and for the intake and exhaust valves as seen here. Later, the engine would be further modified so that the removeable liner of the assembly held the head in place. GE drawing number E-13461. |
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| Left, the diesel engine of the U30, the FDL-16D. One of a number of illustrations from a sales brochure for the U30 which is dated February 1967. 3250 brake horsepower, 3000 HP for traction at 1025 RPM. |
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| Right, illustration of the unitized cylinder assembly in cutaway. Below, GEJ-3847 illustration of the U30, with rectifier panels mounted on blower compartment rear wall. |
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| The U30B was supplied with the long proven General Steel Castings Corporation double equalized road truck. Containing two 752A6 traction motors, with 81/22 gear ratio standard giving top speed of 75 MPH. |
| General Electric had previously introduced its new three axle truck with floating bolster and no equalizers, and this continued in the U30C and U30CG. Three 752A6 motors. |
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| GTA-9 12-pole three phase alternator, which fed three panels of silicon diode full-wave rectifiers. The alternator was designed with growing room for the future; the first test U33 units would soon appear, actually the test U30 units modified. |
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| Above, the 752A6 traction motor. The brochure states that, at the time, the 752 series had amassed over one billion miles in high horsepower road service. The 752 series had begun when GE and ALCO were working together, immediately after World War 2, and had steadily been improved to accept 750 HP per axle by this point in diesel locomotives. In electric locomotives, the E6 used in the E44 produced a total of 4400 HP in six axles, or 733 HP, and the improved mounting used later on the N6 could handle the torque of 5000 HP or 833 HP/axle in the E44A electrics. Field shunting was not employed on the U30. |
| 1966 ad for the U30. Note the number "3000" in the number boards. |
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| At left, a small section of a huge illustration from the U30 brochure, showing the GTA9 alternator and the three rectifier panels mounted on the rear bulkhead of the blower compartment. The six axle units used the same arrangement. Later, after the U33 had appeared, six axle units had their rectifiers mounted on top of the alternator itself. With the U30, GE also introduced other features. For example, the U30 included an entirely new excitation and control system, which used a field transistor to supply excitation. Various inputs controlled the overall time that this transistor conducted, and included provision for automatic power matching after the U30 had been in production for a short time. The power matching was always in effect, unlike that of the U25/U28 which detected, indirectly, traction motor heating and operated (when triggered) for seven minutes. Unlike the U25/U28, which cycled the ORS solenoid on the governor 15 times a minute to reduce excitation (by way of the load regulator) the AC/DC units controlled conduction of the field transistor to effect the power matching function. |
| By the end of 1966, the first U30 production units were built. GE had caught up to ALCO and EMD extremely rapidly, since the first uprated U25 units had appeared in 1965. The new body, improved engine and new transmission - in about a year. |
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| Universal series before the U25. |
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| General Electric U30: Advancing Railroad Progress |