Consolidated Rail Corp., the government-chartered successor to the bankrupt Northeast rail lines, yesterday reported a net loss of $27.6 million for the second quarter on revenues of $867.5 million. A year before, Conrail reported a $34.4 million net loss on $635.9 million in revenues.

Conrail said most of the revenue gains in the April-June quarter were a result of recent rate increases, more thatn offsetting a slight decline in traffic volume caused by a slow recovery from winter.

The railroad said severe winter weather caused more than $100 million of a total of $235.1 million in losses for the first half of 1977.

Other problems listed included Conrail's inability to meet the coal industry's demand for open-top hopper cars, shortages of locomotives and the continued softening of activity in the steel industry.

Conrail Chairman Edward G. Jordan said the railroad expects to meet its 1977 goals for rehabilitation of cars and locomotives, but costs "are up dramatically."

Times Mirror Co. yesterday announced second-quarter net income of $26.5 million (78 cents a share), a 33.5 per cent increase from the $19.8 million (59 cents) earned a year before.

Dr. Franklin D. Murphy, the publishing company's chairman, said second-quarter revenues were $314.8 million compared with $271.7 million a year earlier.