DENVER, Colo. -- Amtrak says it hasn't been able to reach a deal to operate the latest version of Colorado's Ski Train.

The passenger train between Denver and Winter Park shut down last year but Chicago-based Iowa Pacific Holdings has been working to revive it starting this weekend.

As a result of Amtrak’s actions, IPH has filed a multi-million dollar lawsuit against Amtrak, alleging breach of contract. The company was seeking a temporary restraining order so the service could still run. A hearing was scheduled Wednesday in U.S. District Court in Denver..

“We are tremendously saddened that the ski train may not begin a new era of transporting passengers via the scenic mountain rails to Winter Park Resort,” said Ed Ellis, president of IPH. “We were preparing for a celebratory season with much fanfare, and instead, we’re now left to share in the disappointment felt by thousands of passengers who may not be able to experience this tradition.”

The Rio Grande Ski Train was set to begin service on Dec. 27 from Denver’s Union Station. More than 13,000 passengers already have made reservations for the December-March season. The train plans to exchange or refund tickets if it has to delay or cancel its season.

Amtrak has been in talks to provide engineers and conductors but on Tuesday it said they were at an impasse because of issues including staffing requirements and liability.

Amtrak also said it hasn't gotten notice that Iowa Pacific has complied with all federal rail safety regulations. IPH officials said they have followed all regulatory compliance requirements issued by the Federal Railroad Administration and were in the process of inspections when talks with Amtrak stalled.

IPH began marketing and selling tickets in late November 2009 based on successful negotiations between Amtrak and Union Pacific Railroad. Union Pacific owns the tracks and has agreed to let Iowa Pacific use them.

The popular Ski Train had carried skiers to Winter Park since 1940.

In April, the Anschutz Co. sold the train’s cars. At the time, the company said its subsidiary operated the Ski Train at a consistent loss for the past 21 years.