Here's what you need to know about week four of the O-Train shutdown and R1 service

An R1 bus in Ottawa, which is used to replace service on the O-Train Line 1. (CTV News Ottawa)

Transit riders may see out-of-service trains operating on parts of the O-Train line this weekend, but it will be another week before Ottawa's nearly four-year-old light-rail transit system resumes service.

The shutdown of the LRT system is entering a fourth week as work continues to adjust the restraining rails at eight locations along the 12.5 km line and replace the wheel hub assemblies on all light-rail transit vehicles.

The head of OC Transpo says she's confident LRT service will resume on Monday, Aug. 14.

"To our customers, I ask for your continued patience," Transit Services general manager Renee Amilcar said on Friday.

"We are making real progress towards our goal of restoring a safe and reliable service for you."

The work that needs to be done before LRT service resumes includes:

• Reposition 16 restraining rails at 8 locations along the LRT line. Officials have said each restraining rail needs to be adjusted 1 to 2 millimetres
• Ensure all the parameters of the Safety Note from Alstom and Rideau Transit Group "are implemented to ensure the safe operations of the restraining rails," Amilcar said

In addition to adjusting the restraining rails, Rideau Transit Group continues to replace the wheel hub assemblies on LRT vehicles. The new Safety Note requires the leading and trailing wheel hub assemblies and axles to be replaced every 60,000 km.

As of Friday, 18 light-rail vehicles have had their hub assembles replaced and are ready for passenger service.

"Work on the restraining rail adjustments and all areas of the resumption of service will continue over the weekend," Amilcar said.

As part of the return-to-service plan, OC Transpo and RTG will conduct trial running in parallel to the repositioning of the restraining rails.

"Customers may see out-of-service trains in operations in parts of the Line 1 system," OC Transpo said on social media. "These trains are testing the system and are not for customers. Updates on return-to-service will continue to be provided."

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OC Transpo, RTG perform other maintenance work during the LRT shutdown

The three-week shutdown of the light-rail transit system has allowed OC Transpo and Rideau Transit Group to perform other maintenance work on the line, according to officials.

"Obviously, the focus has been very much on the work we need to do to resume service, but we have taken advantage of the fact we have not had trains in passenger service running on the main line," Richard Holder, Director of Engineering Services, told reporters last week.

"There are a number of preventative maintenance activities that have taken place within the corridor."

The O-Train service was temporarily shut down in June for preventative maintenance work on the LRT line and within the tunnel.

"We've also been able to get ahead a little bit on some of the Stage 2 work at the Blair interface, where we're extending the line," Holder said.

"We've been able to give some extra space to the constructor for Stage 2. So there has been other work activities, for sure, over the last two weeks."

Stage 2 will extend the eastern section of the Confederation Line from Blair Station to Trim Road.

Here's what you need to know about R1 service along the O-Train route this week

R1 replacement bus service

R1 replacement bus service continues to run between Blair and Tunney's Pasture stations while the O-Train is out of service.

In downtown Ottawa, R1 replacement bus service is running along Albert and Slater streets, instead of Queen Street, in a bid to avoid traffic delays.

• Westbound R1 buses are running on Albert Street, with stops at Bank and Kent 
• Eastbound R1 buses are running on Slater Street, with stops at Kent and O’Connor 

R1 westbound service will stop at each station between Blair and Tunney's Pasture, except for Lees Station.

A shuttle bus is operating between Lees, uOttawa and Rideau stations.  Customers travelling to Lees station from the east can connect with the shuttle and eastbound R1 service at uOttawa station.

A shuttle bus is also running between Cyrville and St. Laurent stations to connect customers with R1 bus service.

R1 Express

The R1 Express service between Blair Station and downtown Ottawa will operate weekday mornings and afternoons. The R1 Express route will not run on Colonel By Day, but will resume on Tuesday.

The route is identified as "R1 Lyon Express" and "R1 Blair Express" on the bus display.

Buses will run approximately every 15 minutes, according to OC Transpo.

"R1 Lyon Express"

• The R1 Lyon Express will run westbound Monday to Friday, from 6:30 a.m. to 8:30 a.m. (excluding Monday, Aug. 7)
• Bus service will operate from Blair Station to downtown, with stops on the Mackenize King Bridge and on Albert Street at Bank and Kent

The route for OC Transpo's new R1 Express route from Blair Station to downtown Ottawa. (OC Transpo website)"R1 Blair Express"

• The R1 Blair Express will run eastbound Monday to Friday, from 3 p.m. to 6 p.m. (excluding Monday, Aug. 7)
• Bus service will operate from downtown to Blair Station with stops on Slater Street at Bank and Kent and at the Mackenize King Bridge

The route for the new R1 Express service from downtown Ottawa to Blair Station. (OC Transpo website)