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 up to confront a $189 million budget shortfall for FY2011. Watch as the Yellow Line extension disappears on weekdays, then the Yellow Line itself nearly altogether on weekends.

The slideshow appears at the same time that the Coalition for Smarter Growth is pushing an online petition urging elected officials to fully fund the Metro system.