The train is starting to pull out of the station for Ticketmaster and Live Nation’s proposed merger, a venture which is expected to be closely scrutinized by the Justice Department, according to the chair of a Senate antitrust subcommittee and 50 members of the U.S. House of Representatives. Sen. Herb Kohl (D – Wisconsin) raises some concern over merging the nation’s dominant ticket seller with the world’s largest promoter (who also already have a major ticketing service themselves:

“It is clear that this merger raises serious competitive concerns warranting thorough scrutiny,” wrote Kohl to Christine Varney, head of the Justice Department’s antitrust division.

Kohl wrote that the deal would create “an enormous, vertically integrated entertainment giant, which will control everything from artist management, concert promotion, concert venues, and merchandise sales to primary and secondary market ticket sales.”

“The combined entities would be a company of unparalleled size and scope without equal in the market,” he wrote.

“I… urge the Justice Department to carefully scrutinize each of these issues under the antitrust laws, and only approve the merger should it determine that the transaction is unlikely to lead to higher prices for consumers,” wrote Kohl.

Fifty members of the U.S. House of Representatives signed a letter on July 27 written by Rep. Bill Pascrell which also expressed concern about the deal.

“We see little to commend this transaction,” said the letter, which cited “competitive harm in the ticketing and other industry markets” because of the deal.

“Consumers, business managers, artists, independent promoters, and music fans in every state are likely to suffer if the merger is allowed to occur. We urge you to give this transaction the closest possible scrutiny and provide citizens the antitrust protection they deserve,” said the letter.

Live Nation Chief Executive Michael Rapino said in mid-July that he expected the merger to close by the end of the year. We’ll keep you updated as this rolls along.