The Long Long Short Long is the morse code for the letter “Q” Back when the Queen traveled by ship in England, ships with the queen on board would do the LLSL on the horn to announce this to other ships in the harbor to get them out of the way. When the queen switched to traveling by rail, the same signal followed ,and the engineer would do the LLSL coming into the station to allow some space for the Queen. When the US Railroads began, the tradition from England was maintained as the standard signal and it is still used today, over 200 years later!

Thanks for the fun fact, Douglas Mattson at www.myrailmover.com