By Shawn Chitnis

DENVER, (CBS4) – The Denver City Council reviewed a proposal Monday to offer a new contract for operations and maintenance of the underground trains carrying passengers.

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Denver International Airport (credit: CBS)

The trains travel to and from the terminals. The contract would be worth $161.9 million over the next seven years.

Concourse trains at DIA.
(credit: CBS)

Bombardier has been the operator of the trains, and this new contract would keep them in that role from 2018 to 2024.

(credit: CBS)

The day before Thanksgiving a glitch on the trains shut down the service and backed up travelers trying to reach their gates. But airport staff say that was an isolated incident.

Train delays cause passenger backup at DIA on Nov. 22. (credit: Marin Klostermeier)

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The system operates at a rate of 99 percent in terms of on-time service and meeting the demands at Denver International Airport.

(credit: CBS)

“We have a system that is over 20 years old, and we are also increasing in the number of passengers that are coming and utilizing our airport,” said Daria Serna, a spokesperson for DIA.

The contract covers the operation and maintenance of the trains, tunnels, tracks, infrastructure, and power system. Over the past two decades, more passengers keep coming through DIA, pushing the trains to operate more often than when they were first installed.

(credit: CBS)

Council was set to review the contract along with other proposals related to the airport on Monday night during its regularly scheduled meeting.

“It’s really important to keep up the system and to do so we have to make sure we keep up our maintenance,” said Serna.

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Shawn Chitnis reports for CBS4 News at 10 on weekends and CBS4 News at 5 p.m. and 6 p.m. throughout the week. Email him story ideas at smchitnis@cbs.com and connect with him on Twitter or Facebook.