IT'S HERE: The Mike Walker North American Railroad Atlas: NORTHEAST EDITION
Available now:

* Northeast (New Larger Format)
* Appalachia & Piedmont (New Larger Format)
* California & Nevada (New Larger Format)
* Pacific Northwest

Mike Walker, the long-time cartographer behind the industry standard Comprehensive Railroad Atlas of North America, has authorized RailfanDepot to reprint his excellent railroad atlases as they go out of print at SPV.
Next is New England & Canadian Maritimes. (No time frame yet.)