The route section between Rostherne and Warburton would be 7.4km long. The route connecting to Rostherne from the east would be the spur from Manchester Piccadilly (HSM28B from Ardwick). This section provides a chord from Manchester Piccadilly and the Airport interchange station to the through route heading north, HSM21. The design speed would be 200kph (124mph). 3.5km of the route would be over an area of mudstone with soluble deposits (risk of subsidence from dissolution).
A grade separated junction would be provided on the spur from Manchester (HSM28B) with the two line spur increasing to four lines. One chord line would leave the spur on the south side, 200m east of Blackburn’s Brook. The Brook would be crossed on a 75m long viaduct with a height of 4m, followed by a cutting 4m deep. The other chord line would leave the spur on the north side 450m west of the Brook. The chord line on the south side would rise to cross over the spur and the other chord line 600m west of Blackburn’s Brook at a height of 1m above ground level, before descending back into cutting to run parallel to the spur for 700m. This cutting would be 2.4km long with a maximum depth of 13m. Tom Lane would be realigned onto a bridge over the route. The route would pass under the A556 with retaining walls supporting the M56 slip road. Coe Lane would be closed with the route moving north west to pass under the M56 and Reddy Lane. Stabilisation of and support to the A556 and traffic management on the M56 would be required during construction.
The route would then cross Agden Brook on a 95m long viaduct at a height of 4m before passing through the route of overhead power lines. The route would then rise onto an embankment with a maximum height of 7m. The A56 (Agden Brow) would be realigned onto a bridge over the route.
Agden Lane would be closed at the crossing and Warrington Lane diverted for 500m on the west side of the route to avoid it. The route would cross over the Bridgewater Canal. At this point a second grade separated junction would be provided to connect onto the route to the north (HSM21). The western chord line would join the eastern through route line at a junction 100m north of the canal. The eastern chord line would descend to cross under the through route 800m north of the canal, rising back to the level of the through route on the west side. Spring Lane would be realigned onto a bridge over the route and Wet Gate Lane would be diverted for 1km to the west of the route to avoid four crossings of it. The through route and the chord line on its west side would cross over the River Bollin flood plain on a 345m long viaduct at a height of 4m. On the north side of the viaduct a junction would be provided for the chord line to join the through route.
At Warburton the route would continue along section HSM21 to Lowton.
Information taken from HS2 Phase two engineering options report West Midlands to Manchester part 1