A streamlined train.
Explanations of the remaining train idioms from two days ago...
The gravy train: Getting a lot of money for doing very little or nothing. “Gravy” means luxury.
To railroad someone or something: Trains are on tracks; they cannot go where they choose. To “railroad” someone or something is to treat it the same way: to take away choices, to force something or someone, or force something to happen.
A full head of steam: A lot of energy. A train with a “full head of steam” had a boiler filled with steam, and so could go fast.
A whistle stop: at small towns, trains did not always stop. If a passenger was waiting, the station master would sound a whistle as a train approached to tell the engineer to stop. So a “whistle stop” is a short stop at some small town on a trip.
To make the grade: trains have trouble going up hills--”grades.” To reach the top of the hill is to “make the grade.” So to achieve something, like passing an exam, is also “to make the grade.”
A one-track mind: where there was only one track, only one train could move at a time; all other trains had to wait until the track was free. So someone with a “one track mind” can only think of one thing.
End of the line: the end of a railroad—the furthest point the tracks went. So, to “reach the end of the line” is to be in a situation in which you can go no further, do no more.
Picking up steam: gaining energy or interest. Trains “picked up steam” as their boilers got hotter; more water turned into steam, so that they could go faster.
To let off steam: to slow down, and to keep the pressure in the boiler from getting too great, trains often released some steam in a big cloud. This was “letting off steam.” As an idiom, it means doing something to relax or get rid of too much energy. Sometimes you do this by getting angry.
To run out of steam: if a train ran out of steam, it had to stop moving. If a person runs out of steam, they have run out of energy or interest in something.
To get sidetracked: when there was only one track or rail line, all trains but one had to move on to a “side track” next to the main line to get out of the way until the scheduled train passed. In the meantime, they could not move. To “get sidetracked” is to have to stop what you are doing for a while until something else happens.
The wrong side of the tracks: most towns in the days of rail were cut right down the middle by railroad tracks, with the train station being the centre of town. Almost everywhere, one side of the tracks was where the richer people lived, and the other side was where the poor people lived. Usually, this was because of the wind direction. You did not want to be on the side of the tracks towards which the dirty smoke from the train blew. So to be poor is “to come from the wrong side of the tracks.”
Streamlined: designed to reduce air resistance. This became a popular feature of trains during the 1930s or so. It lowered fuel use and increased speed. Now, anything made with clean, straight lines and curves is “streamlined.”
Blowing your stack: getting angry. A train that built up too much steam pressure would have to “blow its stack,” releasing a big cloud of steam.
Milk train; milk run: a slow trip with many stops. Trains used to pick up milk every morning, farm by farm. A very slow process.
A streamlined train.