MTH Premier line P5a Electric locomotive video By Angela Cotey | January 1, 2009 | Last updated on November 7, 2022 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates ALTHOUGH THE SHAPE OF THE P5a BOXCAB bears a strong resemblance to a plastic cheese storage box, don’t let that fool you. This model illustrates the high level of detail that can go into a die-cast metal diesel or locomotive shell.