Railway Zones in India, Classification of Broad Gauge and Meter Gauge line, Various system of railway

Railway Zones:
The entire railway system was earlier divided into nine zonal railways. To increase efficiency, the Railway Ministry decided to line up seven new railway zones, namely, North Western Railway at Jaipur, East Central Railway at Hajipur, East Coast Railway at Bhubaneswar, North Central Railway at Allahabad, South Western Railway at Bangalore, West Central Railway at Jabalpur, and South East Central Railway at Bilaspur. All the new railway zones are fully functional from 1 April 2003.

               Presently, Indian Railways is divided into 17 zones, each having different territorial jurisdictions which vary from 2300 to 7000 route km. The route kilometers of various zonal railways are given in below Table

Sl. No.	Zone	Headquarter
1	Central	Mumbai
2	Eastern Railway	Kolkata
3	Northern railway	Delhi
4	Southern railway	Chennai
5	Western Railway	Mumbai(Church Gate)
6	South Central zone	Secunderabad
7	East Coast	Bhubaneshwar
8	East central	Haajipur
9	North East frontier	Gauhathi
10	North central	Allahabad
11	North East Railway	Gorakhpur
12	North Western Railway	Jaipur
13	West Central Railway	Jabalpur
14	South East	Kolkata
15	South east central	Bilaspur
16	South western railway	Hubballi
17	Konkan getting	Belapur, Navi Mumbai

Total length of broad gauge line in India is 54,257 km which is 84.81 percent of the total length of rail route in the country.

Classification of Broad Gauge Routes:

All the broad gauge (BG) routes of Indian Railways have been classified into five different groups based on speed criteria as given below.

Group A lines

These lines are meant for a sanctioned speed of 160 km/h:

·         New Delhi to Howrah by Rajdhani route

·         New Delhi to Mumbai Central by Frontier Mail/Rajdhani route

·         New Delhi to Chennai Central by Grand Trunk route

·         Howrah to Mumbai VT via Nagpur

Group B lines

These lines are meant for a sanctioned speed of 130 km/h:

·         Allahabad–Itarsi–Bhusaval

·         Kalyan–Wadi Raichur–Madras

·         Kharagpur–Waltair–Vijayawada

·         Wadi–Secunderabad–Kazipet

·         Howrah–Bandel–Burdwan–Barharwa over Farakka–Malda town

·         Barsoi–New Jalpaiguri

·         Sitarampur–Kiul–Patna–Mughalsarai

·         Kiul–Sahibganj–Barharwa

·         Delhi–Ambala Cantt–Kalka

·         Ambala Cantt–Ludhiana–Pathankot

·         Ambala Cantt–Moradabad–Lucknow–Paratapgarh–Mughalsarai

·         Arkonam–Erode–Coimbatore

·         Vadodara–Ahemdabad

·         Jalapet–Bangalore

Group C lines

These lines are meant for suburban sections of Mumbai, Kolkata, and Delhi.

Group D and D Spl lines

These lines are meant for sections where the maximum sanctioned speed is 100 km/h.

Group E and E Spl lines

These lines are meant for other sections and branch lines.

D Spl and E Spl routes: Based on the importance of routes, it has been decided that few selected routes presently falling under D and E routes will be classified as D special and E special routes. This has been done for the purpose of track renewal and priority allotment of funds. The track standards for these routes will be 60-kg 90 ultimate tensile strength (UTS) rails and prestressed concrete (PSC) sleepers with sleeper density of 1660 per km.

Classification of Meter Gauge Routes:

Depending upon the importance of routes, traffic carried, and maximum permissible speed, the metre gauge (MG) tracks of Indian Railways were earlier classified into three main categories, namely, trunk routes, main lines, and branch lines. These track standards have since been revised and now the MG routes have been classified as Q, R1, R2, R3, and S routes as discussed below.

Q routes: Routes with a maximum permissible speed of more than 75 kmph. The traffic density is generally more than 2.5 GMT [gross million tonne(s) per km/annum].

R routes: Routes with a speed potential of 75 kmph and a traffic density of more than 1.5 GMT. R routes have further been classified into three categories depending upon the volume of traffic.

1. R1—traffic density more than 5 GMT
2. R2—traffic density between 2.5 and 5 GMT
3. R3—traffic density between 1.5 and 2.5 GMT

Various system of railway:

1. Surface railway: The railways provided over the ground surface are known as surface railways.
2.  Elevated railway: The railways provided at higher or elevated portion, above the ground surface are called elevated railways. In this system a continuous viaduct supported on piers, columns etc. is constructed and the track is carried on its steel deck. 
3. Underground railway: The railways provided just below the ground level is known as underground railways.
4. Tube railway: The railways provided underground at a greater depth of about 18m or more upto 52m are called tube railway.