Retrofitting infrastructure for skip-stop operation on urban railways

초록

This paper addresses retrofitting infrastructure to operate express trains together with existing normal trains in the urban railway. The Korean railway started first operation of urban railway in the capital area since 1974. Currently, seven different companies operate 18 lines in the area. However, most of the lines operate in single all-stop pattern. Now, 42 years have passed from the first operation, citizens in the area want faster urban railway service. Many Korean passenger have experienced advantages of the faster service from KTX (first Korean high speed railway, 2004) and Seoul Metro-9 (first full-dressed express/normal service urban railway in Korea, 2009). Unfortunately, most infrastructure of the lines in the area had not constructed to be able to combined operation of express and normal trains. Practically, the lines had not facilitated sidings for meet-overtaking operation as well as selected signaling system with high performance enough to control skip-stop operation within sufficiently short overtaking time. This paper deals with methods and issues of retrofitting the existing infrastructure to make the lines possible to enable skip-stop operation in the urban railway. However, many difficulties exist in retrofitting the infrastructure. Many stations in the lines were constructed underground, moreover many of them were surrounded by building nearby. Therefore constructing additional sidings to the existing line is fairly difficult. The difficulties can be understood in two major issues amongst many others. First, undergoing train operation can be affected by the construction work in high possibility. This may cause inconvenience to citizen, and some of them, particularly who may not benefit from the retrofitting, may blame implementation of itself. Second, cost for the retrofitting is calculated too high. KRRI (Korea Railroad Research Institute) have calculated the cost to 150 million dollars for constructing additional sidings in single underground station. Third, many of other stations cannot even start retrofitting by rules and guidelines, despite the two major issues are under considered. This paper presents two case studies on the retrofitting the existing infrastructure in the Korean urban railways. First, a case of Bundang line operated by KORAIL (Korea Railroad), and second, a case of line #6 operated by SMRT (Seoul Metropolitan Rapid Transit Co.). In addition, it addresses findings and experience in research on the retrofitting of the existing infrastructure to operate express and normal trains combined in a single line.