Signal training : Construction and maintenance of lines : Ground cable - Engeland Voorschrift, 26/GS Publications/1550 Signal training. Pamphlet No. 1: Construction and maintenance of lines : Field cables - Engeland Voorschrift, 26/GS Publications/652 Signal training. Pamphlet No. 1: Construction and maintenance of lines : Principles of construction - Engeland Voorschrift, 26/GS Pubns/387