Navajo Mine Railroad  The Navajo Mine Railroad is an electrified private railroad operated by BHP in New Mexico, USA, within the Navajo Nation. It operates of track between the Four Corners Generating Station and Navajo Coal Mine (formerly owned by BHP). The railroad does not have any connection to the national rail network. A -long standard gauge line was built in 1974 from the power plant to the Hosteen stockpile. The line was expanded to the present in 1983. Since there is no connection to the rest of the railroad network, the 3 diesel locomotives and 22 Maxon bottom dump coal hopper cars had to be transported from Gallup on low-bed trucks. At the beginning only one train operated. There were problems with clogged oil bath filters on the diesel locomotives due to excessive coal dust, but the issues were solved with a new filter type. Electric operation started 1984 since it is more economical. Diesel operation became too expensive with the increasing train loads and fuel prices. Furthermore another 20 hopper cars were purchased in order that two trains could be built, each having 18 cars. Electric operations are being dismantled in favor of the new GE ET44AC diesel locomotives with more on the way. The line runs from the Navajo Mine north-northwest to the Four Corners Generating Station, which is located west of Farmington, New Mexico. It has no connection to any other railroad. The trains are operated with an electric locomotive E60 on the North end and a diesel locomotive ALCO Century 425\0, where this one acts normally as a dummy. It serves normally only as a control cab to for the radio remote controlled E60, when the empty train is heading back to the mine. The prime mover is still present to provide emergency power in case of an electricity outage. There are two trains in operation, theoretically a third train could be operated. Each train consist of 21 coal hoppers. Both trains make typically 12 round trips a day in a 24 hour operation. There is only one crew member at work, who takes an empty train to the coal load out, where he changes to the full train to drive it back to the power plant. While this train is underway, the other one gets loaded. The catenary has a voltage of 25 kV 60 Hz AC. The pantographs of the E60s are mounted on top of pedestals on the roof to adapt their working height to the unusually high catenary height. Extra filters for cleaning the machine room air are mounted on the roof of the locomotive.