16-16  Basic Statistics on National Railways in Operation
Item	1985	1990	1995	2000	2005	2006
Length of Railways in Operation      (km)	52119	53378	54616	58656	62200	63412
In Formal Operation	49433	50310	50866	51262	57589	58901
In Temporary Operation	2686	3068	3750	7394	4611	4511
Proportion of the Length in Formal	94.8	94.3	93.1	87.4	92.6	92.9
Operation
Double-Tracking Length                    (km)	9989	13024	16909	21408	24497	25244
As Percentage of the Length of Railways	19.2	24.4	31.0	36.5	39.4	39.8
in Operation
Length of Electrified Railways          (km)	4151	6941	9703	14864	19408	23435
As Percentage of Railways in Operation	8.0	13.0	17.8	25.3	31.2	37.0
Length of Diesel Engine Routes        (km)	10822	16097	24749	39497	42792	39976
As Percentage of Railways in Operation	20.8	30.2	45.3	67.3	68.8	63.0
Length under Centralized Traffic Control (km)	1307	1169	1226	1200	1828	4181
As Percentage of Railways in Operation	2.5	2.2	2.2	2.0	2.9	6.6
Automatic Blocking Length              (km)	6921	10370	12910	18318	24149	25630
As Percentage of Railways in Operation	13.3	19.4	23.6	31.2	38.8	40.4
Semi-automatic Blocking Length     (km)	42625	38832	40859	41695	39390	39145
As Percentage of Railways in Operation	81.8	72.7	74.8	71.1	63.3	61.7
Length of Continuous Welded Rail (km)	10439	14644	21854	29975	47965	53296
As Percentage of the Trunk Lines	16.7	21.7	40.0	51.1	54.2	60.2
Relay Interlocking Station              (unit)						4121
As Percentage of Stations in Operation						73.9
Computer Interlocking Station              (unit)						1299
As Percentage of Stations in Operation						23.3
a) Four indicators of relay interlocking station, percentage to the station in operation, and computer interlocking station, percentage to the station in
operation are increased since 2006.