Figure 1 from Intermediate block signalling (IBS). A cost effective method to increase throughput of railways | Semantic Scholar
East Coast Railway on Twitter: "3/n running in the direction towards the block station. When the block section is too long (more than 8km), to improve track utilization, IBS (Intermediate Block Section)
East Coast Railway on Twitter: "#ECoRKnowledgeByte ABSOLUTE BLOCK SYSTEM 1/n A system which allows only one train at a time in a block section is called as ABSOLUTE BLOCK SYSTEM. No train
Absolute Block
Home Signal Limits and Block Sections (from Pachl [2004]) | Download Scientific Diagram
Semiautomatic Block Signaling | Article about Semiautomatic Block Signaling by The Free Dictionary