Union Pacific 1

I have been researching the railroad industry lately and the nerd in me enjoys understanding the minutae of how it works.  So, I was happy to stumble upon a basic glossary of rail terminology offered by the Paducah & Louisville Railroad.  Some of the more interesting and sometimes humorous terms include:

High Wide: Oversized (height or width exceeding standards) or overweight loads. NOTE: carloads not exceeding 11’4″ in height from the top of the railcar’s bottom (15’6″ above rail for loaded railcar) or which are less than 10’8″ wide are usually considered “Standard”.  Standard maximum gross weight for the PAL is 163,000 pounds per car or car capacity, whichever is the least.

Hump Yard: A switching yard built on an incline where, after movements by the engine, the cars are shunted by gravitational pull to their destination in a yard.

Mother/Slug: Power Unit/Power Mate; two locomotive units operating in tandem, both of which are equipped with traction motors (which furnish the tractive power to the rail, physically moving the train along the tracks); only one of the locomotive bodies is equipped with diesel engine and main generator which provide the electric power for traction motors in both units.  The crew can operate the train from the cab of either unit. The Power Unit (“MOTHER”) can operate independently of the Power Mate(“SLUG”); the Power Mate cannot operate independently of the Power Unit.

For the record, the Paducah & Lousivlle Railroad is a Class II Railroad.  The Surface Transportation Board classifies Class I railroads as those having operating revenues of $250 million or more.  Class I railroads include CSX, BNSF, Amtrak, Union Pacific, Norfolk Southern and Kansas City Southern.  The Paducah and Louisville is Class II railroad, having more than $20.5 million in annual revenue, and Class III railroads have less than $20 million in revenue and are frequently local or switching railroads.


I grew up in a town with two railroad tracks, and lived just a block away from the rails.  I saw and heard so many trains I mostly never noticed they were there.  However, I never remember seeing a caboose.   According to the Union Pacific Railroad the history of the caboose is as follows:

The origins of both the car and the word are surrounded as much by legend as by fact. One popular version dates the word back to a derivation of the Dutch word “kombuis,” which referred to a ship’s galley. Use of cabooses began in the 1830s, when railroads housed trainmen in shanties built onto boxcars or flatcars.

The addition of the cupola – the lookout post atop the car – is attributed to a conductor who discovered in 1863 that he could see his train much better if he sat atop boxes and peered through the hole in the roof of his boxcar.

The caboose served as shelter at the rear of the train, minimal housing quarters, and an office for the conductor.  The famous cupola on topcaboose 2 provided an elevated perch to inspect the condition of the trains from above.

The caboose was required by law for safety reasons, but in the 1980’s technology replaced the beloved and humble caboose.  Flash rear-end devices (FRED) replaced the caboose, electronically telling engineers about approaching trains as well as brake line pressure and accidental train separation.  However, the beginning of the end actually occurred in with the advent of the air break and longer trains such that the conductor could no longer see the entire length of the train.  Also:

New labor agreements reduced the hours of service required for train crews and eliminated the need for cabooses as lodging. Cabooses, when used at all, were drawn from “pools” and no longer assigned to individual conductors.

However, the caboose is not dead.  The image still sears in the memory of rail enthusiasts.  You can even buy and rent cabooses.  You can also rent hotel rooms in old cabooses used as lodges and bed and breakfasts.

caboose 3