Apart from obsessing about snow, we’ve lost a good chunk of time today playing with David Alpert’s neato slideshow depicting the evolution of the Metrorail system over time. Mr. Greater Greater Washington was clearly keeping busy during the Snowmaggedon, and if you’re even remotely geeky about transit, you should check it out. Don’t fail to take note of the “future” maps at the end, which depict possible major service cuts looming as WMATA gears…