What is an 'A' class line, or a 'Q' class line, etc.?

The permanent way sections are classified by IR according to the maximum speed (or more precisely, the maximum speed proposed for the immediate future) that the tracks are capable of supporting. In most cases this classification is more an indication of the priority of the route and IR's plans for it in the future, rather than an indication of the speeds allowed on it today. Also, some small stretches of a line may have much higher (or lower) allowed speeds than the classification of the line might indicate because of local conditions, ghat sections, curves, etc.

The trivia section includes a list of the maximum speeds that some of these sections have been cleared for .

A class: Lines in this class are BG sections rated for speeds up to 160km/h. Some of these are:

Most of the New Delhi - Howrah line (via Grand Chord and Howrah-Burdwan Chord ('Rajdhani route')). New Delhi - Bombay Central ('Frontier Mail route' or 'Golden Temple Mail route') New Delhi - Madras Central ('Grand Trunk route') Howrah - Nagpur - Bombay V.T. (CSTM) Ratnagiri - Sawantwadi (KR) Ratnagiri - Sawantwadi is a recent addition to this group [2004?]. Some IR publications still [2/06] do not list this section as an 'A' route.

Apart from the standard 'A' class lines mentioned above, IR is contemplating setting up some very high speed sections. Proposed sections include Mumbai Central - Ahmedabad, Bangalore - Chennai Central (these two for up to 200km/h, with the former also being a candidate for a Shinkansen-like service with trains at up to 300km/h -- although this is still in the early stages of planning), and Palwal-Bina, Ghaziabad-Mughalsara (these two for routinely running passenger trains up to 160km/h, and freights at 100km/h). These new sections will be fully fenced or grade-separated.

B class: This class allows speeds up to 130km/h. This class includes the following sections (from 1999 unless otherwise indicated):

Allahabad - Katni - Jabalpur - Itarsi - Bhusaval Kalyan - Pune - Daund - Wadi - Secunderabad - Kazipet Vadodara - Ahmedabad Mathura - Ratlam Ahmedabad - Ajmer - Jaipur - Bandikui - Rewari - Delhi Sitarampur - Madhupur - Kiul - Patna - Mughalsarai Howrah - Bandel - Barddhaman Kharagpur - Waltair - Vijayawada Kiul - Bhagalpur - Sahibganj - Barharwa Delhi - Panipet - Ambala Cantt. - Kalka Ambala Cantt. - Ludhiana - Pathankot Ambala Cantt. - Moradabad - Lucknow - Pratapgarh - Mughalsarai Agra Cantt. - Lalitpur Kanpur-Agra (As of [2/00] there was a plan to upgrade this and Lucknow-Kanpur to 'A' and rate it at 140km/h.) Virar - Vadodara - Godhra Lalitpur - Bina Khanna - Barharwa - Farakka Bridge - Malda Town Wadi - Raichur - Arakkonam - Madras Central Jolarpettai - Bangalore Arakkonam - Jolarpettai - Salem - Erode - Coimbatore - Ernakulam New Jalpaiguri - Malda Town (NFR) Chennai Beach - Dindigul [2005] Chennai Beach - Chennai Egmore (3rd line) [2005] Bangalore - Dharmavaram - Gooty [2004] Ghaziabad - Saharanpur [2005] C class: This is not really a speed-rated class, but is the classification used for suburban sections of metropolitan areas.

CST Mumbai - Kalyan - Kasara CST Mumbai - Kalyan - Karjat CST Mumbai - Kurla - Panvel CST Mumbai - Ravali - Mahim - Andheri CST Mumbai - Ravali - Kurla Churchgate - Mumbai Central - Borivali - Virar Chennai Central - Basin Bridge Jn. - Veyasarapadi - Arakkonam Chennai Central - Basin Bridge Jn. - Washermanpet - Chennai Beach - Tambaram Chennai Central - Basin Bridge Jn. - Korukkupet - Tondiarpet - Tiruvottiyar - Gummidipundi Chennai Beach - Thirumayilai Sealdah - Dumdum - Naihati - Kalyani - Ranaghat - Krishnanagar Sealdah - Sonarpur - Baruipur Ballygunge - Budge Budge Howrah - Dankuni - Saktigarh - Barddhaman Howrah - Bandel - Saktigarh Seoraphuli - Tarakeshwar Dumdum - Barasat Howrah - Panskura - Kharagpur D-special class: BG lines rated up to 100km/h, with high traffic density or high expected growth in traffic. The following lines were identified as D-special routes in 1999 unless otherwise indicated:

Kharagpur - Midnapur - Adra Barkakhana - Barwadih - Garwa Road Tundla - Yamuna Bridge Bolangir - Titlagarh Gudur - Renigunta Anara - Chandil - Kandra - Sini Anuppur - Shahdol - Katni - Bina Ahmedabad - Viramgam Nagda - Ujjain - Maksi - Bhopal Lucknow - Sultanpur - Zafarabad Jn - Varanasi Delhi - Ghaziabad - Hapur - Moradabad Lucknow - Kanpur (In [2/00], there was a proposal to upgrade this to 'A'.)) Chapra - Hajipur - Barauni Raipur - Titlagarh - Vizianagaram Guntakal - Tornagallu - Hospet (Hospet section added 2004) Udhna - Nandurbar - Jalgaon Gomoh - Chandrapura [2005] Garwa Road - Chopan [2005] Garwa Road - SoneNagar [2005] Barauni - Katihar [2005] Sambalpur - Talcher - Nergundi [2005] Jharsuguda - Bolangir [2005] Barabanki - Gonda - Gorakhpur - Chhapra [2005] Champa - Gewra Road [2005] Bilaspur - Anuppur [2005] D class: BG lines rated up to 100km/h.

Salem - Bayappanahalli Guntur - Donakonda - Guntakal Vikarabad - Parli - Parbhani Vijayawada - Bhimavaram - Nidadavolu Secunderabad - Dronachalam Jodhpur - Marwar Diva - Vasai Rd (Was E-Special until recently [2004].) Pen - Roha Kumedpur - Katihar Jn Rewari - Hissar Kalumna - Nagda (via Itwari) Kota - Ruthiyai Bina - Guna - Ruthiyai E-special class: BG lines with sanctioned speeds below 100km/h, with high traffic density or high expected growth in traffic. The following lines were identified as E-Special routes in 1999:

Garwa Road - Sonnagar Panskura - Haldia Talcher - Rajatgarh - Salegaon - Nergundi Cuttack - Paradeep Radhakishorepur - Rajathgarh - Barang Kapilas Road - Salegaon Radhakishorepur - Machapur Kirandul - Koraput Rajakharshwan - Dongaposi - Padapahar - Barajmda - Gua Bondamunda - Bimlagarh - Barsuan - Kiriburu Kandra - Gomhauria (Gamharria) Champa - Gevra Road Marauda - Dallirajhara Urkura - Sarona Bhojudih - Mohuda (Grand Chord) Chandil - Muri - Bokaro - Rajbera Padapahar - Banspani Jharsuguda - Sambalpur - Bolangir Barajamda - Bolanikhandan Muri - Barakakana Talgoria - Bokaro City Kota - Ruthiyal Diva - Vasai Road (formerly [1999]; now D class) Tornagallu - Hospet (formerly [1999]; now D class) Andal - Sainthia [2004] Hatia - Muri [2004] Mohuda - Gomoh [2004] Koraput - Kottavalasa [2004] Koraput - Singapuram Road [2004] Sambalpur - Angul [2004] Anuppur - Bijuri - Boridand [2004] Boridand - Bisrampur [2004] Durg - Marauda [2004] Londa - Vasco [2004] Dewas - Maksi [2004] Gandhidham - Bhuj [2004] Dornakal - Bhadrachalam Road - Manuguni - Kerapalli & Singereni collieries [2004] Sanathnagar - Maula Ali (bypass line) [2004] E class: This class includes all other BG lines with sanctioned speeds below 100km/h.

Q class: These are MG lines rated for speeds above 75km/h and traffic generally above 2.5 GMT. Some (such as Delhi - Jaipur) allowed speeds up to 105km/h or so (Pink City Exp., etc.) and had concrete sleepers and welded rails. The list of such lines from 1999/2000 is given below; gauge conversion has rapidly changed the MG picture in recent years.

'Q' class MG sections as of 1999/2000 Rewari - Ringus - Phulera Ratangarh - Degana Delhi Sarai Rohilla - Rewari - Ratangarh Ajmer - Ratlam - Khandwa Jaipur - Phulera - Ajmer Bandikui - Agra Fort Ahmedabad - Bhavnagar Agra - Mathura - Bhojipura - Lalkuan Bhojipura - Lucknow Jn Villupuram - Thanjavur - Thiruchirapalli Chennai Beach - Villupuram (added in 2000) Dindigul - Madurai (added in 2000) In addition to the above, these MG sections were in the 'Q' class in 1985 (incomplete list):

'Q' class MG sections as of 1985 Ratangarh - Rewari Jodhpur - Jaipur - Agra East Bank Kathgodam - Bhojipur Bangalore - Hubli - Miraj R class: These are MG lines rated at up to 75km/h. This category is further broken down into three classes based on traffic density: R-1, R-2, and R-3 (in decreasing order of traffic carried).

R-1 routes (traffic above 5 GMT/year) : As of 1985, this included Hospet - Hubli, Secunderabad - Guntakal, Londa - Marmagoa, Katihar - New Bongaigaon, Guwahati - Tinsukia, and Gandhidham - Palanpur. Only Gandhidham - Palanpur remained in this category by 1999. Katihar - New Bongaigaon and Guwahati - Tinsukia carry over 5 GMT / year, but are not counted as R-1 routes as they are slated for gauge conversion very soon [2004]. R-2 routes (traffic of 2.5-5.0 GMT/year) : As of 1985, this included Guntakal - Hospet, Guntakal - Villupuram, Tiruchirapalli - Manamadurai - Virudunagar, Purna - Secunderabad, and Jodhpur - Marwar. By 1999, the list consisted of just Secunderabad - Mudkhed, Guntakal - Bellary, Guntakal - Villupuram, Thiruchirapalli - Manamadurai - Virudunagar. R-3 routes (traffic of 1.5-2.5 GMT/year) : As of 1985, this included Madurai - Rameswaram, Virudhunagar - Tenkasi, Dindigul - Pollachi, Ratangarh - Bikaner - Merta Rd., Muzaffarpur - Narkatiyaganj, and Birur - Shimoga Town. By 1999, the list consisted of Madurai - Rameswaram, Virudunagar - Tenkasi, Dindigul - Pollachi, and Ratangarh - Bikaner. S class: These are all the remaining MG lines rated for below 75km/h and/or with low traffic densities (below 1.5 GMT/year).

There are no classifications like the above for narrow gauge tracks.

As mentioned above, these speeds are the maximum that the tracks are built to support. Actual running speeds are usually much lower because of other considerations (traffic on the line, signalling arrangements, curves, proximity to populated areas, presence of points and divergences / convergences, etc.). Based on this the maximum permissible speed is specified for each section of a route.

Normally only the main line can be traversed at that speed. Turnouts to diverging routes require a reduction in speed. Most turnouts have speed restrictions of 25km/h (1 in 12 or easier). Sharp turnouts (1 in 8, NG turnouts of 1 in 8.5, etc.) are limited to 15km/h or even 10km/h or 5km/h in some cases. (A few NG lines have even sharper turnouts; e.g., the DHR has a 1 in 5 turnout and 1:4 crossings. Speeds are restricted appropriately in such cases.) In practice many of these are crossed at higher speeds depending on local conditions and the driver's knowledge of the track.

RDSO Proposed BG Turnout Speed Restrictions
Turnout	Speed Restriction
1:8.5 turnout with straight switch	10 km/h
1:8.5 turnout with curved switch	25 km/h
1:12 turnout with straight switch	15 km/h
1:12 turnout with conventional curved switch (0°27'35" switch entry angle)	40 km/h
1:12 turnout with improved curved switch	50 km/h
1:12 turnout with thick web switch	50 km/h
1:16 turnout with symmetrical split curved switch	75 km/h
1:16 turnout with conventional curved switch	50 km/h
1:16 turnout with high speed curved switch	60 km/h

Note that some railbuses and other vehicles are allowed a higher speed than normal on sharp turnouts because of their smaller wheels. Several high-speed turnouts are now being installed that allow passage at 40km/h, mostly to speed up passage of freight trains. The presence of curves, insufficient cant, etc. can further require reductions in allowed speed.

Traffic based classification Some older documents and other sources of IR make reference to a purely traffic-based classification system for tracks. This system appears no longer to be in use. In this, lines were classified as: 'HM' or Heavy Mineral - BG mineral and ore freight lines; 'A' - BG lines with more than 3 million gross tonnes or MG lines with more than 2 million gross tonnes of traffic; 'B' - BG lines with 0.75 to 3 million gross tonnes or MG lines with 0.5 to 2 million gross tonnes; 'C' - BG lines with 0.5 to 0.75 million gross tonnes of traffic, or in some cases, defined as any lines carrying 3 or fewer trains a day; and 'D' - light lines with no or little existing traffic built for passenger services or for the purpose of stimulating commercial activity in underdeveloped areas.

Source - IFRCA.org