According to the Have Your Say, City of Mandurah website:
To lift the bridge structure into place, temporary road and railway closures will be required.
In order to lift over the railway, the overhead power must be switched off, and there can not be trains operating along that section of line. As a result, trains between Mandurah and Rockingham will be temporarily disrupted from about 8pm on Friday July 31 until the first timetabled service on Monday August 3.
The last full line service on July 31 departs Perth at 6.55pm. The last full line service departing Mandurah leaves at 7.20pm. Train replacement bus route 909 will operate. Replacement bus services will be provided during the rail closure. Commuters are urged to plan their journey and can do so by visiting the Transperth website or calling the Transperth Info Line on 13 62 13.
The temporary Mandurah Road closure will be implemented between Murdoch Drive/Allnutt Street and Mandjoorgoordap Drive. This will occur from 8pm on July 31 to 4am on August 3. Detours will be in place and every effort will be made to minimise inconvenience to road users, however some delay is expected.
The bridge lift is subject to satisfactory weather conditions.