This station is based off the 2007-2009 Allston Multimodal Study which indicates three tracks with an island platform serving two. No way they'd only put in a single side platform - they learned their lesson from the Newton stops and Yawkey. An outbound side platform would require a bridge anyway, so they're going with an island serving two of three tracks. That way, you can get away with a ramp to Everett Street.
That said, however, the rendering in the 2009 study indicates an Arthur Street bridge as well.
...Anyone else note the California cars in slide 5 of Arlington's link?
That said, however, the rendering in the 2009 study indicates an Arthur Street bridge as well.
...Anyone else note the California cars in slide 5 of Arlington's link?