Ottawa city councillors have a big decision to make next week: whether to approve a pair of contracts worth nearly $4.7 billion, the richest procurement the city has ever undertaken.

The second stage of Ottawa's light rail project has grown from 30 kilometres of track to 44 kilometres, and from 19 stations to 24, extending the public transit system deeper into the suburbs of Orléans and Riverside South than first envisioned.

The price has grown, too, by $1.2 billion, but only about $700 million of that comes from the add-ons: the rest is thanks to the increasing cost of scarce skilled labour, and the rapidly rising price of materials due to global trade factors far beyond the city's control.

Here's what Ottawa would get for that $4.7 billion.

Going south

TransitNEXT, a wholly owned subsidiary of SNC-Lavalin, is the city's top pick to extend the Trillium Line to the south, to upgrade existing O-Train stations and to maintain the line for the next three decades.

Originally, the line was supposed to end at Bowesville Road, south of the airport, but the Ontario government committed $50 million and developers Urbandale and Richcraft chipped in another $30 million to stretch it an extra 3.4 kilometres to Limebank station at Riverside South.

In addition to maintaining the line, TransitNEXT would upgrade existing O-Train stations and:

Build a cycling and pedestrian bridge over the Rideau River near Carleton University, and a pedestrian walkway between Bayview station and Trinity Group's development at 900 Albert St.

Build a grade-separated crossing for O-Train and Via Rail tracks in the Mooney's Bay area.

Upgrade the rail tunnel under Dow's Lake.

Build a new train garage at Walkley station.

Included in the contract is $97 million for seven of Stadler's extra-long FLIRT diesel trains. The city also plans to continue using its existing Alstom LINT trains on the Trillium Line..

Passengers from the airport will transfer to the main Trillium Line at South Keys. (City of Ottawa)

A spur line would connect directly to the departures level at the Ottawa International Airport. Trains from the airport would run every 12 minutes, and also stop at the EY Centre at Uplands station. (This rendering is a placeholder only.) (City of Ottawa)

Bowesville station will have a park-and-ride lot with 800 spaces for passengers from Greely, Manotick and Metcalfe. One stop to the north, Leitrim station will have 330 spaces. (City of Ottawa)

The Trillium Line will open first, in the fall of 2022. For Carleton University students, it will mean a two-year bus detour. (City of Ottawa)

Connecting east and west

A joint venture called East-West Connectors came out on top to expand the Confederation Line with a bid worth $2.57 billion. That's nearly $600 million over the cap the city set, but hundreds of millions less than the nearest bidder.

The consortium won't be responsible for maintaining the Confederation Line in the long term. That job already went to Rideau Transit Group, builders of the first stage of light rail.

It, too, has become a larger project than initially planned and includes:

A train garage just beyond Moodie station.

​A pedestrian walkway over the Queensway to Baxter Road, and two pedestrian underpasses below the Sir John A. Macdonald Parkway

Various bridge and water main upgrades

Nor does East-West Connectors need to build trains. The city has already purchased the 38 vehicles it needs through Rideau Transit Group. They're the same Citadis Spirit model that has been struggling as the project lags behind schedule.

East to Trim Road

East of Blair Station, which is set to open during first stage, all five Stage 2 LRT stations will be located on the median of Highway 174, including Orléans Boulevard station, seen here. (City of Ottawa)

The bus station at Place d'Orléans will be converted for LRT. Bus passengers will use an existing pedestrian bridge to transfer to light rail. (City of Ottawa)

Trim station will be the Confederation Line's eastern terminus.

Expanding light rail east from Blair Road could be completed by the fall of 2024, still two years later than originally planned. (City of Ottawa)

West to Moodie Drive

Cleary station, seen here, and New Orchard station will be open-air stations that act as bookends for a section of the western Confederation Line that will travel below street level under the Byron Linear Park. (City of Ottawa)

A new pedestrian bridge will span Highway 417 from the new Queensview station to Baxter Road, near IKEA. (City of Ottawa)

Moodie station will mark the western terminus of the Confederation Line, tucked between the Highway 417 exit and Corkstown Road. Beyond it would be garages for the trains, to be built alongside the Queensway. (City of Ottawa)