Small Towns With Lots of Railroads - Classic Trains Magazine

White River Jct VT was served by the B&M, CV and Woodstock Ry.  CP trains became B&M trains at Wells River, 35 miles north of White River Jct.  CP and B&M had various power pool arrangements which resulted in CP power being handled at B&M's Westboro roundhouse across the Connecticut River in West Lebanon, NH.

Some to add:

St. Johnsbury VT with MEC, CP And St. Johnsbury & Lamoille County. Wells River VT with B&M, CP and Montpelier & Wells River. Claremont NH with B&M, CV and Claremont & Concord.  Charlestown NH with B&M, CV and Springfield Terminal.  Bellows Falls VT, with B&M, CV and Rutland.  Brattleboro VT had B&M, CV and West River RR.

The line between White River Jct VT and East Northfield MA was jointly operated by B&M and CV.  CV owned between WRJ and Windsor, B&M between Windsor and Brattleboro. 

B&M and CV each had a line between Brattleboro and E. Northfield MA. B&M's  was on the east side of the Connecticut in NH. The lines were operated as paired track, CV north, B&M south, until B&M's bridge abutment at E. Northfield failed in 1969.  Lines operated under B&M dispatcher and rules except for CV between Brattleboro and E. Northfield.