The L Train is marijuana cigar or "blunt. Comprised of 3 normal cigar that has been sliced open, emptied, and combined together at there ends. Then after drying, re-rolled with marijuana inside.
The Red Line is an elevated train that provides 24-hour train service between Howard on the North Side and 95th/Dan Ryan on the South Side via downtown Chicago. Do not take this train day/night to or from the south side of Chicago if you are white unless you want to get beat up, jumped or raped.
New girl living on south side: "hey let's take the Red Line "L" Train up to the city"
Friend who's been living there: "yeah girl, we can take the Red Line "L" Train if you want to get raped, beat up, stabbed and have your phone and money stolen"
Based on the name for the train in New York L-train is a name pimps like to give themselves considering that the L-train has 24 stops. So being L-trained simply means having a train run on you by a pimp named L-train or having a twenty four person train run on you. Also there was a well known pimp in Akron Ohio who was well known for running L-trains . Coincidentally he called himself L-train.