Transportation with rails is a form of transportation that uses rails or tracks to move people and goods. The most common example of this type of transportation is a train, but other forms include trams, monorails, and even sleds. The term 'SLED' is a four-letter word that refers to a vehicle that is pulled by a horse or other animal, and is often used for recreational purposes. However, it can also be used as a form of transportation with rails, as it can be pulled along a track or rail.