I'd like to know if the phrase "murky yellow cars" in this excerpt from the chapter Nine from The Great Gatsby by F. Scott Fitzgerald means "murky and yellow cabs" or "cabs of a murky yellow":
And last the murky yellow cars of the Chicago, Milwaukee and St. Paul railroad looking cheerful as Christmas itself on the tracks beside the gate.
The passage in Chapter Nine of The Great Gatsby refers to "murky yellow cars," not cabs. People referred to passenger cars as "cars" quite often in the days when railroads were the major form of interurban transportation. Freight cars would have been referred to as "boxcars." The "murky yellow cars" are evidently the color of the passenger cars used on the Chicago, Milwaukee & St. Paul Railroad. They probably looked murky at that time of year (near Christmas) because in that northern region they could have gotten spattered with mud and snow, and even the windows could have been hard to see out of because of being smeared with dirt and mud. According to Wikipedia:
The Chicago, Milwaukee, St. Paul and Pacific Railroad (often referred to as the Milwaukee Road) was a Class I railroad that operated in the Midwest and Northwest of the United States from 1847 until 1980, when its Pacific Extension was embargoed through the states of Montana, Idaho, and Washington.
The yellow cars had nothing to do with Yellow Cabs, which probably did not even exist at the time The Great Gatsby was written. These cars would undoubtedly have been "sleeping cars" or "Pullman cars." Chicago was the hub of all the Western and Midwestern railroads. It was hard to get anywhere by rail without passing through Chicago, which is the terminus Fitzgerald is describing in the passage in Chapter Nine. Milwaukee is the main city in Wisconsin, and St. Paul is a major city in Minnesota.
F. Scott Fitzgerald was born in St. Paul, Minnesota on September 24, 1896. In the Chapter Nine of the novel Nick Carraway writes:
Those who went farther than Chicago would gather in the old dim Union Station at six o'clock on a December evening, with a few Chicago friends, already caught up into their own holiday gayeties, to bid them a hasty good-by.
But this is evidently Fitzgerald himself reminiscing autobiographically. He attended The Newman Academy in Hackensack, New Jersey and later went to Princeton, so he must have done a lot of traveling by railroad from east to west and west to east. Travel was long and tedious in those days. The trip from New Jersey to Minnesota would have taken about three days and nights.