n 1945, the Services Commissions were set up at Bombay, Calcutta, Madras and Lucknow. In 1948, the Indian Railway Enquiry Committee reviewed working of commissions.In 1949, due to financial constraints a ban was imposed on recruitments on Indian Railways thus numbers of commissions was reduced to one centrally located at Bombay.In 1953-54 when Economic conditions of Indian Railway improved, four service commission were again set up at Bombay, Madras, Allahabad and Calcutta.
In 1956, the Estimates committee generally approved the method of recruitment by the constitution of the Railway Service Commissions. In 1983, to cater to the needs of areas which were being neglected due to locations of the existing commissions, seven more commissions were set up viz, at Ahmedabad, Ajmer, Bhopal, Bhuvneshwar, Chandigarh, Jammu and Srinagar with sitting at Leh and Trivendrum. In 1984 two more service commissions were set up at Malda and Gorakhpur. In January, 1985 Railway Service Commissions have been renamed as Railway Recruitment Board (RRB). At present 19 Railway Recruitment Boards are functioning.
On long distance routes and also on some shorter routes, IR uses 2 primary types of coach design types. ICF coaches, in production from 1955 until Jan 2018, constitute the bulk of the current stock. These coaches, considered to be having inadequate safety features, are slowly being phased out. As of September 2017, around 40,000 coaches are still in operation. The older coaches are being replaced with LHB coaches. Introduced in mid ’90s, these coaches are lighter, safer and are capable of speeds up to 160 kilometres per hour (99 mph)
As of March 2017, IR network spans 121,407 km (75,439 mi) of track length, while the route length is 67,368 km (41,861 mi). Track sections are rated for speeds ranging from 80 to 200 km/h (50 to 124 mph), though the maximum speed attained by passenger trains is 180 km/h (110 mph). As of March 2017, most of the broad-gauge network is equipped with long-welded rails, pre-stressed concrete (PSC) sleepers and high tensile strength 52kg/60kg 90 UTS rails.
Official Notification >> http://rrbajmer.gov.in/upload_pdf/rrbajmer2.pdf