3.5 Assembly Technology and Technical Requirement for Turnout Steel Rail Piece
3.5.1 Turnout slab resurveying
The turnout slab shall be surveyed again before laying，and it can be laid only after resurveying data is qualified.The resurveying mainly includes the plane coordinates of all prism points and the height of rail supporting layers（rail supporting points）.
3.5.2 Rail pieces hoisting，placing and installation
1.Rail piece hoisting in place
The special carrying pole and flexible gallus shall be used to hoist and place rail pieces，the rail pieces shall be gently lifted and gently fell down，meanwhile，flexible rope shall be used to pull and drage，to reduce falling and lifting impact，avoid fell damage and transformation to turnout components.The arranging spacing for carrying pole hoisting points shall not be more than 6m，the rail terminal shall not be more than 8m to the nearest hoisting point，and the deflection between two hoisting points shall not be more than 100mm.In switch rail lifting，all lifting points position shall be moved 1m to switch rail tail end.Any loading and unloading means which may cause plastic transformation must be prohibited.Rail heads shall be kept upward in loading and unloading operation，and rail overturning is strictly forbidden in loading and unloading operation.
2.Rail piece installation
Shunting machine，middle connecting parts，rail frog pieces shall be placed according to turnout setting out points，and 8mm rail gap shall be reserved.The installation sequence is：switch rail assembling unit of stock rails shall be installed first，which longitudinal position shall be adjusted according to control points，fasteners shall be installed，and bolts shall be painted with grease，installed with flat washer and fastened；then the adjustable frog center part shall be installed，the top end of frog rail shall be adjusted to setting out point，and then adjusted longitudinally and transversely by track lifting machine，enabling the base plate with jacking block to align with the bolt hole on track slab，other base plates shall also be adjusted，eccentric taper sleeve，coverplate，coil spring shall be installed，and bolts shall be fastened；finally the guide rail shall be installed，middle washer shall be place，the rail shall be moved to middle base plated with crowbar manually and placed in groove，the gaps between guide rail，stock rails and switch rail shall be adjusted and controlled within 8mm，eccentric taper sleeve，coverplate，coil spring shall be installed，and bolts shall be fastened.
3.5.3 Turnout line shape fine adjustment
The turnout line shape shall be roughly aligned after turnout assembly is completed.
Main turnout track direction shall be adjusted，the special wire wheel shall be adopted to adjusted stock rails FAKOP（“dynamic track gauge optimization”abbreviation in German，refers to a special structure of switch rail and stock rail which can optimize vehicle dynamics），the FAKOP surveying point at every switch tie shall be 100mm to datum mark.Bolts and elastic strip fastener shall be fastened after fine adjustment，the gap between the middle ring of elastic strip and bottom rail shall be controlled within 1mm，it shall be completely fastened after fine adjustment，the gap between the middle ring of elastic strip and bottom rail shall be controlled less than 0.5mm，the torque of T-shaped bolt shall reach 300 N·m.The longitudinal relative position of straight and curve stock rails shall be adjusted，and the rail head anvil mark at the tracting point shall be taken as the benchmark by angle rule.
The relative position of stock rail and switch rail shall be adjusted taking the anvil mark as benchmark by angle rule.
The elastic strip fastening torque shall be 180～200 N·m，the spacing between the middle ring of the elastic strip and the bottom rail surface layer shall be 0.1～0.5mm during installation.
The stock rails and switch rail shall be checked whether they are closely attached and it shall be less than or equal to 0.5mm，only 0.5mm feeler gauge can be inserted for measurement，and the feeler gauge over 0.5mm is not allowed to be used.The position of limiting stopper shall be adjusted，the gap at both sides shall be measured and the difference shall not be more than 0.5mm.