2　Prefabrication and Production ofCRTSⅡBi-block Sleeper

2.1　Basic Structural Requirement for Sleeper Yard

2.1.1　Function division of the yard

To take the sleeper yard for Zhengzhou-Xi’an passenger dedicated railway of China Railway First Group Co.，Ltd.as an example（Figure 7），the basic structure of the sleeper yard includes office and living area，sleeper production area，batching plant and sleeper storage area.The sleeper yard occupies about 50 mu（1 mu≈666.67 m2）.

The production function area includes office and living area，laboratory，boiler room，power distribution room and material management，etc.

The total length of Zhengzhou-Xi’an passenger dedicated railway is 436 km； the Zheng Xi sleeper yard of China Railway First Group Co.，Ltd.undertakes the production task of 260 000 Zublin bi-block sleepers for 85 km of tender sections ZXZQ06 and ZXZQ10.Based on the already known sleeper production task and requirement of construction period，1 sleeper production line is installed in the sleeper production workshop，90 sets 2×2 formworks are installed calculated at 25 day/month，the design production capacity is 18 000 sticks/month.

1.Sleeper production area

Sleeper production area mainly includes sleeper production line，steam curing area，sleeper inspection area and rebar processing area.

2.Batching plant

The batching plant is next to the sleeper production area，the discharged material is directly delivered to the concrete distributing bucket in the workshop.The batching plant model is set upon the maximum design daily productivity.The electronic weighing instrument and centralized computer control are adopted as the management style，to increase the concrete quality.

That the laboratory is next to the batching plant makes the overall layout of the production area more compact and reasonable.

3.Sleeper storage area

The sleeper storage area is used to temporarily store the bi-block sleepers.

The sleepers shall be stored in batches.The ground surface of the finished product warehouse can be hardened by concrete or with strip foundation； the gantry crane or forklift shall be used to stack the sleepers not over 12 layers，5 sleepers for each layer.The 10 cm ×10 cm stow-wood shall be inserted between each layer of sleepers.

2.1.2　Basic principle for position selection of sleeper yard

Since the bi-block sleepers are small structural prefabrication products，they can be transported to the laying site by trucks.Considering the factors like truck transport，construction road condition，and transportation cost，the supply scope of the prefabrication yard shall be radiating from center to surrounding areas，and shall generally be restricted within 50 km range.