In the first part of this series, we saw that the present conditions are most favorable for the GT-EL, a clean burning train hauling machine, to make a comeback and become a winner. In this article, the author discusses how UPRR, GE and ALCO came together on the first locomotive and tested it.
Union Pacific Railroad (UPRR), GE and ALCO got together on the first 4500 HP GT locomotive. UPRR insisted on burning Bunker ‘C’ fuel because of UPRR's connection with Richfield Oil Company and because such fuel was cheap considering the low 16 to 18 percent efficiency of the proposed new GT. Buckland and his engineers designed the 4500 HP GT and a demonstrator test unit was delivered by ALCO to UPRR in 1948. Together, GE, ALCO and UPRR tested the unit.
The unit was packaged by ALCO whereby ALCO furnished the frame and body and GE the electrical parts and gas turbine in a joint venture arrangement. After the tests started, UPRR called the unit the ‘big blow’ because of the loud noise it made. It was also known as UP 50. In 1951, an order for 25 of the 4500 HP units was given to GE and ALCO by UPRR. The package was often called by other railroads the GE/ALCO gas turbine locomotive. There were two refinements and improvements along the way between batches of deliveries.
Bunker ‘C’ fuel was nasty stuff to handle and burn in the new GT, but diesel fuel cost too much. Buckland and his team came up with a way to burn the stuff. Tests showed that the fuel had a high content of sodium and vanadium and the ash (vanadium pent oxide) caused hot corrosion problems that literally ate up the combustor cans, nozzle vanes and rotation blades. The TBOs were not acceptable and the blading was expensive.
First stage blades
The GT nozzle and first stage blades were made out of a high nickel Nimonic 80A alloy, the best high temperature material known at the time. This alloy was developed by the UK Frank Whittle Lab. The corrosive ash ate right through this costly material. The team came up with a solution – a slurry of Epsom Salt and water was mixed with the Bunker ‘C’ and then centrifuged before this so treated fuel was burned. Water took out the sodium and the Epsom Salt neutralized the Vanadium pentoxide. The TBOs were much better but were still high being about 4000 to 5000 hours of operation.
Another problem was inlet air filtration. The first inlet filters did not take out enough of the sand and grit and as a result prematurely eroded the compressor blading. Work had to be done in this area to make the GT's TBOs acceptable.
The original design of the GT was called the ‘turkey design’ by the GE shop engineers and workers because the turbine section of the GT was not horizontally split and the exhaust end had to be stood up vertically, and the compressor and combustor sections had to be lifted off vertically and stuffed back in vertically like stuffing a turkey. There was a close fitting spline coupling that connected the compressor and combustor sections shafting to the turbine shaft. It was difficult to disassemble and then reassemble the unit. The procedure was time consuming and costly. The spline fitting had to be just right to prevent excessive vibration from occurring. The GE Salt Lake City service shop was used to do the overhaul work on the gas turbines under an agreement with UPRR.
GE 12000 HP Frame 5 gas turbine
The first design of the 4500 HP unit was only partially successful as a locomotive driver. UPRR was not completely satisfied. GE, after a few years, in 1957 then designed a larger 12000 HP sized simple cycle single shaft GT with a horizontally split turbine casing. The unit was down rated to 8500 HP at 6000 feet elevation and 90o F inlet air temperature to satisfy UPRR for the high hills around Utah and Wyoming. The new GT was a great improvement but still was costly to maintain burning Bunker ‘C’ fuel. During 1958 to 61, UPRR ordered a total of 30 of the new GT packages. This 8500 plus HP unit was the largest locomotive ever built in the world and still is. Because of its large size (two cabs), it was called the ‘Super Big Boy’ by UPRR.
The older UPRR original Frame 3 units were retired after the new Frame 5 unit came along. The new Frame 5s ran better and were used by UPRR for several years before they were also retired late in the 1960s. It can be said that the GT-EL episode was not completely successful as no other railroad company bought any of the units. However, UPRR considered the GT-EL successful and said the rising cost of Bunker ‘C’ and # 6 fuel oil by the oil companies forced them to retire the ‘Big Boys’ and ‘Super Big Boys’.
In his next article, the author talks about the progress of diesel engines and discusses other applications of the Frame 3 and 5 HD units.
(This article is the second part of a series by the author.)
Ivan G. Rice was past chairman of the South Texas Section of ASME (1974 - 75), past chairman of the ASME Gas Turbine Division (now IGTI) (1975 - 76). A Life Fellow Member of ASME and Life Member of NSPE/TSPE, he has authored many articles and ASME papers on gas turbines, inter-cooling, reheat, HRSGs, steam cooling and steam injection.