Table:
text: British Rail Railbuses
BR Railbuses
BR Railbuses
Number_Range Builder Introduced No_Built Region Withdrawn
79958-59 Bristol / Eastern Coach Works 1958 2 Scotland 1966
79960-64 WMD Donauwörth 1958 5 Eastern Region/London Midland 1967
79965-69 D Wickham & Co 1958 5 Scotland 1966
79970-74 Park Royal Vehicles 1958 5 London Midland / Scotland 1968
79975-79 AC Cars 1958 5 Scotland / Western Region 1968
999507 Elliot Wickham 1958 1 Departmental 1997

Question: What is the minimum established department region in British Rail Railbuses?

Question: What is the lowest introduced value for British Rail railbuses?