Hearts took another big step towards promotion with a 3-1 win at 10-man Raith.Goals from Kevin McHattie, Jamie Walker and Billy King secured a seventh straight win and moved the Edinburgh side an incredible 20 points clear at the top of the Scottish Championship.McHattie marked his first appearance since November with the opening goal after 26 minutes, tapping in James Keatings' deflected effort from close range.Raith grabbed an equaliser two minutes before half-time when Ryan Conroy's corner was headed in by Craig Barr.But Rovers were reduced to 10 men in the 64th minute when Christian Nade was sent off for a foul on McHattie.Hearts made their advantage count after 79 minutes when Walker cut in from the left and slammed a low shot into the far corner.And with five minutes remaining Walker teed-up King to wrap up the points.