X15p is a class of narrow gauge electric multiple units to be operated by SL on the Roslag Railway.

[4] The name follows Swedish tradition for rail vehicle names, in which X means electric multiple unit, and the last p means 891 mm gauge.

A new depot, Vallentunadepån, has been constructed near Molnby, about 3,5 kilometers north of Vallentuna, in order to house the new trains.

The depot contains space for all of the 22 new trains, with the ability to conduct maintenance on them as well.

The older X10p rolling stock will still be housed at the depot in Mörby.