Covers the systems that ensure only one train occupies a block section at a time — from older electro-mechanical block instruments through electrical and fully automatic block signalling. Includes real operational concepts like IBS (Intermediate Block Signal), MACLS (Modified Automatic Colour Light Signalling), and gate stop signal placement rules.
Real Exam Facts — IBS & MACLS
- IBS (Intermediate Block Signal) introduction into a section with a slip siding requires specific corresponding changes — a real, tested scenario.
- In MACLS territory, the Gate Stop Signal is located specifically in rear of the level crossing gate it protects — a precise positioning rule.
Content Status
Draft note, grounded in real official syllabus text found via research but not yet cross-checked against the primary RBE PDF directly. Treat as study-aid only until verified.