Union Pacific 844 is a class "FEF-3" 4-8-4 "Northern" type steam locomotive owned and operated by the Union Pacific Railroad for its heritage fleet. Built in December 1944 by the American Locomotive Company (ALCO) of Schenectady, New York, No. 844 is one of four surviving FEF series locomotives and the only one in operation.

#fef884 color RGB value is (254,248,132). #fef884 hex color red value is 254, green value is 248 and the blue value of its RGB is 132. Cylindrical-coordinate representations (also known as …

Union Pacific Railroad No. 844 is an FEF-3 class 4-8-4 "Northern" type steam locomotive owned by the Union Pacific Railroad (UP). Built by the American Locomotive Company (ALCO) in December 1944, it was the last steam locomotive delivered to the UP and is the only steam locomotive never retired by a major North American class I railroad.

Union Pacific 844 is a 4-8-4 steam locomotive which the Union Pacific dubbed, originally enough, "Four-Eight-Fours" and classed them as such (Class FEF-1 through FEF-3).

The first class, designated FEF-1, for Four Eight Four, comprised numbers 800-819. Fitted with 77-inch drivers and a 300-pound boiler pressure, UP was impressed by their performance and took delivery of 15 additional 4-8-4 locomotives in Aug-Oct 1939, numbers 820-834.

2023年4月1日 · Herein, via an in-situ strategy, the ultrafine FeF 3 particles are intimately embedded in double-enhanced conductive Fe/graphitized carbon (GC) matrices for the first time to obtain FeF 3 /Fe/GC cathode materials with a three-dimensional spongy structure.

2019年2月1日 · Electrochemical tests demonstrate that the well designed FeF 3 ·0.33H 2 O single crystal (FFH-S) delivers 30 mAh g −1 higher capacity (172 mAh g −1 at 0.1C) than the common FeF 3 ·0.33H 2 O polycrystal (FFH-P). In-situ XRD combined with theoretic calculation elucidate the difference in lithium storage capacity.

2019年3月27日 · 此款轮式的实际运用之一是美国联合太平洋铁路公司（以下简称“联太铁路”）从美国机车公司订购的FEF系列蒸汽机车⑴。 在20世纪30年代初，联太铁路的干线客运蒸汽机车主力为1922年到1924年间从美国机车公司订购的4-8-2“山岳”轮式MT-1型和MT-2型蒸汽机车⑵。 但到30年代末期，这些“山岳”轮式机车已经不能应付持续上升的铁路运输量，这个问题限制了联太铁路的客运业务发展。 在1937年，联太铁路主席William Jeffer所乘坐的一列由“山岳”轮式 机车牵引 的 …

Steam Locomotive No. 844 is the last steam locomotive built for Union Pacific Railroad. It was delivered in 1944. A high-speed passenger engine, it pulled such widely known trains as the Overland Limited, Los Angeles Limited, Portland Rose and Challenger.

Steam locomotive 844 was built in 1944 by the American Locomotive Company and is the only steam locomotive to never be retired from a major railroad in the United States. 844 was also the last new...