Deputy mayor Norm Kelly says the troubled renovation of Toronto's Union Station is a "wake-up call" for city officials who might want to take on other large infrastructure projects.

"I would expect staff to look more closely at all the options that are on the table, rather than stay with one particular model," Mr. Kelly told reporters on Monday.

The acting mayor was responding to a Globe and Mail report that the $800-million renovation of Canada's busiest multimodal transit hub is plagued by mismanagement, infighting, cost overruns and needless delays. The project is operating without an approved schedule.

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Hundreds of e-mails and reports obtained by The Globe through a freedom of information request reveal that, for more than a year, city officials have struggled to manage problems at Union Station.

Many of the daily squabbles are showcased in e-mails from March and April, 2013.

Take the case of the $30,000 elevator buttons.

The commuter rail service GO Transit had asked for extra large buttons in its new elevators at Union Station for accessibility reasons. The city agreed, but when the supplier offered a smaller option for a fraction of the price, officials took the opportunity to save money. When GO found out, it demanded to get what was outlined in the contract. After a brief investigation, the city learned the mistake would mean an extra two weeks per elevator. It is unclear how many elevators were affected, but a city consultant wrote on March 27, 2013, that "the additional cost for the remaining seven elevators will be in the order of $32,932.82."

One of the documents indicated that GO did not want to be stuck with the additional cost. The company's Lesley Thompson sent an e-mail to those involved: "I'm not clear on why the cost of these buttons would be extra to GO. The [oversized] buttons were specified in the tender documents and GO never accepted an alternate."

Eventually, according to an e-mail, the city told GO it would figure out the cost with Carillion, the company hired to manage the project. Carillion, which has refused numerous interview requests, was the subject of much complaining from city bureaucrats.

"Gentlemen," began an April 9, 2013, e-mail from Rick Tolkunow, a principal engineer for the city on the project to staff and companies involved, including Carillion. "We need an immediate meeting to discuss the major cost discrepancies" around work on "moat" covers. Carillion had provided pricing that in some cases was "almost 10 times the original estimate," Mr. Tolkunow wrote. (It's not clear if the work had begun or was still in negotiation.) Mr. Tolkunow asked Carillion to explain. A little more than two weeks later, it appeared the city had not had a reply.

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"Before I send a nasty e-mail to [Carillion], did any of you get the requested rationalization/reconciliation of the budget variances from our meeting?" Mr. Tolkunow wrote on April 30, 2013.

No one had.

"Okay, then I will send my e-mail," Mr. Tolkunow concluded.

The most prevalent complaint concerned the lack of a schedule. In early 2013, Carillion presented the city with a revised timeline option. The city rejected it.

"The city is clearly disappointed and frustrated with the results of hundreds of thousands of dollars spent on schedule development on this project to date," John Spinelli the city's manager of construction, wrote in a May 15, 2013, letter marked "Draft."

Two sources involved in the Union Station project said the city should not be handling developments of such size.

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When asked if it was a mistake to take on something as complex as the overhaul of a 100-year-old building – still operating – with heritage issues, rather than hire a private firm, the Toronto bureaucrat in charge of the project would not comment.

"There's no question this is unusual for the city to be directly executing an $800-million project," said Richard Coveduck, Toronto's director of design and construction.

City councillor Denzil Minnan-Wong, who chairs the public works committee, said he is concerned about the situation.

"This might be a reason why we should be looking at more public-private partnerships. The private sector brings in private sector discipline, where projects are finished on time and on budget."