Further more,it is the first time to jack in a three-hole frame culvert below a single-span auxiliary girder.

Research on the safety of railway auxiliary girder when jacking method is used in construction;

In the extension and reconstruction of box culverts on operating lines,the flexible use of construction auxiliary girders and reasonable arrangement of work process play a key role in shortening the train speed restriction time,reducing as far as possible the disturbance of construction on operation and ensuring construction safety and engineering quality.

The technology of line reinforced by the temporary beam in the D pattern and container bridge jacking has been widely applied.

The sped of train is limited to 45 km/h on the temporary beam aecording to the rule stipulated in "Rules of Railway Engineering and Maintenance Safety" , but in fact, the speed of train on the temporary beam is often increased to 60 km/h or more in order to reduce the influence on traffic by construction.

When the underpass bridge frame structure in the Ganlong Line from Ganzhou of Jiangxi province to Longyan of Fujian province below which is the Jingjiu Line is carried out with jack-in method, Jingjiu Line is supported by 6 pairs of temporary beams in the pattern of D16+ D24+ D16 to ensure the normal function of it.