G&SR Important Definitions – Part 2
Rule 1.02: Definitions 21 to 40 | Railway Operating Department LDCE Exam
The General and Subsidiary Rules (G&SR) are one of the most important areas of study for Railway Operating Department LDCE, GDCE and other Departmental Examinations.
In Part 1, we studied Definitions 1 to 20 under Rule 1.02. In this second part, we will study Definitions 21 to 40 with their official meaning, simple explanation, examples wherever necessary, and important LDCE Exam Points.
This part contains several fundamental Operating terms such as Facing and Trailing Points, Fixed Signal, Fouling Mark, Interlocking, Intermediate Block Post, Isolation, Last Stop Signal, Line Clear, Main Line and Material Train.
Important Current Update
The traditional sequence of Rule 1.02 has now received an important addition. Under the Indian Railways (Open Lines) General (Third Amendment) Rules, 2024, a new Definition 28A – Indian Railway Automatic Train Protection System (IR-ATP/Kavach) has been inserted after Definition 28. The official amendment was incorporated through Railway G&SR amendment material in 2025.
Therefore, this Part includes 28A – Kavach at its correct position, while the existing Definitions 29–40 retain their numbers.
21. Facing and Trailing Points
Official G&SR Definition
The terms Facing and Trailing Points are determined according to the direction in which a train or vehicle moves over the points.
Points are Facing Points when, by their operation, a train approaching them can be directly diverted from the line on which it is running to another line.
Simple Explanation
Whether a set of points is called Facing or Trailing depends upon the direction of movement of the train or vehicle.
When a train approaches the points from a direction in which operation of those points can divert the train from one line to another, they are Facing Points for that movement.
When the same points are approached from the opposite direction, they are Trailing Points.
Example
If a train approaching a turnout can be diverted from the Main Line to a Loop Line by operating the points, those points are Facing Points for that train movement.
LDCE Exam Point
Facing/Trailing is determined with reference to the direction of movement of the Train or Vehicle.
22. Fixed Signal
Official G&SR Definition
A Fixed Signal is a signal of fixed location indicating a condition affecting the movement of a train.
Simple Explanation
A Fixed Signal is permanently installed at a specified location and conveys an indication that affects the movement of trains.
It is an essential part of the railway signalling system.
LDCE Exam Point
Remember:
Fixed Location + Indication affecting Train Movement
23. Fouling Mark
Official G&SR Definition
Fouling Mark means the mark at which the standard dimensions between two lines intersecting or converging towards each other are infringed.
Simple Explanation
Where two railway lines converge or intersect, a point is reached beyond which a vehicle standing on one line may interfere with the safe movement of a train or vehicle on the adjoining line.
The Fouling Mark identifies this safety limit.
Example
A wagon left beyond the safe Fouling Mark on one line may foul the adjoining line and create a collision hazard.
LDCE Exam Point
Fouling Mark → Safe clearance between converging/intersecting lines.
24. Gangman
Official G&SR Definition
Gangman means a Railway Servant employed on permanent way or any work connected therewith.
Simple Explanation
A Railway Servant engaged in work connected with the railway track/permanent way is covered by this definition.
LDCE Exam Point
Gangman → Permanent Way/Track-related work
25. Gangmate
Official G&SR Definition
Gangmate means the person in charge of a gang of workmen employed on permanent way or any work connected therewith.
Simple Explanation
A Gangmate is the person responsible for a gang of workers engaged in track/permanent-way related work.
Remember the Difference
Gangman → Worker engaged on Permanent Way
Gangmate → Person in charge of the Gang
26. Gateman
Official G&SR Definition
Gateman means a competent Railway Servant posted at a level crossing for working the gates.
Simple Explanation
A Gateman is a Competent Railway Servant posted at a Level Crossing for operation of the level-crossing gate.
LDCE Exam Point
Gateman = Competent Railway Servant + Level Crossing + Gate Working
27. Goods Train
Official G&SR Definition
A Goods Train, other than a Material Train, is a train intended solely or mainly for the carriage of animals or goods.
Simple Explanation
A train intended for carrying goods or animals is a Goods Train.
The definition specifically distinguishes it from a Material Train.
LDCE Exam Point
Goods Train ≠ Material Train
Study Definition 39 – Material Train along with this definition.
28. Guard
Official G&SR Definition
Guard means the Railway Servant in charge of a train and includes a brakeman or any other Railway Servant who may, for the time being, be performing the duties of a Guard.
Simple Explanation
The term Guard is not restricted only to a Railway Servant holding the regular designation of Guard.
It also includes another Railway Servant who is, for the time being, duly performing the duties of the Guard.
LDCE Exam Point
Guard = Railway Servant in charge of Train + person performing Guard's duties for the time being.
28A. Indian Railway Automatic Train Protection System
IR-ATP (Kavach) — Important Latest Addition
Current G&SR Provision
IR-ATP (Kavach) is a radio-communication-based control system provided as an additional aid to Loco Pilots of functional Kavach-fitted locomotives while operating in Kavach territory.
The rule further makes an extremely important point: use of Kavach does not override the provisions of codes and manuals governing regular train operation that are required to be followed by the Loco Pilot.
Simple Explanation
Kavach is an Automatic Train Protection system designed to provide additional assistance to the Loco Pilot.
However, Kavach does not mean that the Loco Pilot can ignore normal operating rules, signals, codes or manuals.
The Loco Pilot remains responsible for following the prescribed rules of train operation.
Why This Is Important for LDCE
This definition was not part of the traditional 60-definition list in older G&SR editions.
It was inserted as Definition 28A under the Third Amendment Rules, 2024 and therefore deserves special attention for current Operating Department examinations.
LDCE Exam Point
Remember three elements:
Kavach = Radio Communication Based Control System + Additional Aid to Loco Pilot + Does Not Override Regular Operating Rules
29. Inspector of Way or Works
Official G&SR Definition
Inspector of Way or Works means any Inspector or Assistant Inspector responsible for the construction or maintenance of permanent way, points and signals, bridges or other works connected therewith.
Simple Explanation
This definition covers an Inspector or Assistant Inspector responsible for construction or maintenance connected with—
Permanent Way, Points and Signals, Bridges and related Works.
LDCE Exam Point
Remember both:
Construction + Maintenance
30. Interlocking
Official G&SR Definition
Interlocking means an arrangement of signals, points and other appliances, operated from a panel or lever frame, so interconnected by mechanical locking, electrical locking or both that their operation must take place in the proper sequence to ensure safety.
Simple Explanation
Interlocking is a fundamental safety arrangement.
Signals, Points and related equipment are interconnected so that they can be operated only in a safe and proper sequence.
This helps prevent conflicting or unsafe movements.
Example
Before a signal can be taken OFF for a particular route, the interlocking system ensures that the required points and other safety conditions are correctly established.
LDCE Exam Point
Remember:
Signals + Points + Locking + Proper Sequence + Safety
Interlocking is a high-priority Operating LDCE topic.
31. Intermediate Block Post
(IBP)
Official G&SR Definition
An Intermediate Block Post is a Class ‘C’ station on a single line, double line or multiple line, remotely controlled from the Block Station in rear.
Simple Explanation
An Intermediate Block Post (IBP) is a Class C Station controlled remotely from the Block Station in rear.
It is associated with the division and working of a longer Block Section.
LDCE Exam Point
IBP = Class C Station + Remote Control from Block Station in Rear
32. Intermediate Block Signalling
(IBS)
Official G&SR Definition
Intermediate Block Signalling is an arrangement on a single, double or multiple line by which a long Block Section is split into two portions, each constituting a separate Block Section, by providing an Intermediate Block Post.
Simple Explanation
Under Intermediate Block Signalling (IBS), one long Block Section is divided into two separate Block Sections by providing an Intermediate Block Post.
LDCE Exam Point
Long Block Section → IBP → Two Separate Block Sections
Study Together
IBP ↔ IBS
These two definitions should always be studied together.
33. Isolation
Official G&SR Definition
Isolation means an arrangement, secured by the setting of points or other approved means, to protect a line from the danger of obstruction from other connected lines.
Simple Explanation
Isolation is a safety arrangement designed to prevent an obstruction or unintended vehicle movement from one connected line from endangering another line.
It may be achieved through Points or other approved arrangements.
Example
If a vehicle standing in a siding starts moving unintentionally, a proper isolation arrangement can prevent it from fouling a Running Line.
LDCE Exam Point
Isolation → Protection from danger of obstruction from connected lines
34. Last Stop Signal
(LSS)
Official G&SR Definition
Last Stop Signal means the fixed Stop Signal controlling the entry of trains into the Block Section in advance.
Simple Explanation
The Last Stop Signal (LSS) is the last fixed Stop Signal governing a train's entry into the Block Section ahead.
Its relationship with Block Working is therefore extremely important.
LDCE Exam Point
LSS → Controls entry of Train into Block Section in advance
This is one of the most important definitions for Operating LDCE.
35. Level Crossing
Official G&SR Definition
Level Crossing means the intersection of road with railway track at the same level.
Simple Explanation
A place where a road and railway track cross each other at the same level is a Level Crossing.
LDCE Exam Point
Road + Railway Track + Same Level = Level Crossing
36. Level Crossing Gate
Official G&SR Definition
A Level Crossing Gate means any form of movable barrier, including a chain, capable of being closed across the road at a level crossing, but does not include a wicket or turnstile intended for the use of pedestrians.
Simple Explanation
A movable barrier used to close road traffic at a Level Crossing is a Level Crossing Gate.
A chain can be included in the definition.
However, a pedestrian wicket or turnstile is excluded.
LDCE Exam Point
Chain → Included
Pedestrian Wicket/Turnstile → Not Included
37. Line Clear
Official G&SR Definition
Line Clear means the permission from a Block Station to a Block Station in rear for a train to leave the latter and approach the former, or the permission obtained by a Block Station from a Block Station in advance for a train to leave the former and proceed towards the latter.
Simple Explanation
Line Clear is the permission exchanged between adjoining Block Stations before a train is allowed to proceed into the relevant Block Section under the applicable System of Working.
Example
Before a train is despatched from Station A towards Station B, Station A obtains the prescribed Line Clear from Station B under the applicable Block Working rules.
Very Important Concept
Line Clear and Authority to Proceed are not the same thing.
Line Clear is associated with permission between Block Stations, whereas Authority to Proceed is the authority given to the Loco Pilot to enter the Block Section with his train.
LDCE Exam Point
Study these three definitions together:
Line Clear ↔ Authority to Proceed ↔ Block Section
38. Main Line
Official G&SR Definition
Main Line means the line ordinarily used for running trains through and between stations.
Simple Explanation
The Main Line is the line ordinarily used by trains for normal through movement, including movement between stations.
LDCE Exam Point
Main Line → Line ordinarily used for through train movement
Do not automatically treat every Running Line as a Main Line.
39. Material Train
Official G&SR Definition
A Material Train is a departmental train intended solely or mainly for carrying railway material when picked up or put down for execution of works either between stations or within station limits.
Simple Explanation
A Material Train is a Departmental Train used mainly in connection with railway works.
It may carry railway material to be picked up or deposited at work locations between stations or within Station Limits.
Example
A departmental train used for transporting and placing track material at an engineering worksite may be operated as a Material Train subject to the applicable rules.
LDCE Exam Point
Material Train = Departmental Train + Railway Material + Execution of Works
Important Difference
Goods Train → Commercial goods/animals
Material Train → Departmental railway material/work
40. Mixed Train
Official G&SR Definition
Mixed Train means a train intended for the carriage of passengers and goods, or passengers, animals and goods.
Simple Explanation
A train used for carrying a combination of Passengers and Goods, or Passengers, Animals and Goods, is a Mixed Train.
LDCE Exam Point
Compare:
Passenger Train → Mainly Passengers/Coaching Traffic
Goods Train → Goods/Animals
Material Train → Departmental Railway Material
Mixed Train → Passengers + Goods/Animals
Quick Revision – Definitions 21 to 40 + 28A
| No. | Definition | Key Point |
|---|
| 21 | Facing & Trailing Points | Depends upon direction of movement |
| 22 | Fixed Signal | Fixed location; affects train movement |
| 23 | Fouling Mark | Safe clearance between lines |
| 24 | Gangman | Permanent Way-related work |
| 25 | Gangmate | In charge of Gang |
| 26 | Gateman | Competent Railway Servant at Level Crossing |
| 27 | Goods Train | Goods/animals; not Material Train |
| 28 | Guard | Railway Servant in charge of Train |
| 28A | IR-ATP (Kavach) | Additional ATP aid; does not override operating rules |
| 29 | Inspector of Way or Works | Construction/Maintenance |
| 30 | Interlocking | Safe sequence of Signals/Points |
| 31 | IBP | Class C Station; remote control |
| 32 | IBS | Long Block Section divided into two |
| 33 | Isolation | Protection against obstruction |
| 34 | Last Stop Signal | Controls entry into Block Section ahead |
| 35 | Level Crossing | Road/Track crossing at same level |
| 36 | Level Crossing Gate | Movable road barrier |
| 37 | Line Clear | Permission between Block Stations |
| 38 | Main Line | Ordinarily used for through movement |
| 39 | Material Train | Departmental train for railway works |
| 40 | Mixed Train | Passengers + Goods/Animals |
⭐ Most Important Definitions for Operating LDCE
For Operating Department LDCE, the following definitions from Part 2 deserve particularly close attention:
1. Interlocking — Understand the relationship between Signals, Points, Locking, Proper Sequence and Safety.
2. Last Stop Signal (LSS) — Remember its direct relationship with entry into the Block Section in advance.
3. Line Clear — One of the fundamental Block Working concepts. Do not confuse it with Authority to Proceed.
4. Intermediate Block Post (IBP) — Remember Class C Station and remote control from the Block Station in rear.
5. Intermediate Block Signalling (IBS) — Understand how a long Block Section is divided into two separate Block Sections.
6. Isolation — Its purpose is protection against the danger of obstruction from connected lines.
7. Facing and Trailing Points — Classification depends on the direction in which the Train/Vehicle moves over the Points.
8. Fouling Mark — Understand its connection with safe clearance and protection of adjoining lines.
9. Fixed Signal — A foundation definition for the complete Signalling portion of the syllabus.
10. Line Clear ↔ Authority to Proceed — Their difference is particularly important for conceptual questions.
11. Goods Train ↔ Material Train ↔ Mixed Train — Prepare these as comparative definitions.
12. IR-ATP (Kavach) — This deserves special attention because 28A is a newly inserted definition under the 2024 amendment rather than part of the older traditional list. The official amendment explicitly states that Kavach is an additional aid and does not override the codes/manuals governing regular train operation.
Study These Definitions Together
Facing Points ↔ Trailing Points
Fouling Mark ↔ Isolation
IBP ↔ IBS
Last Stop Signal ↔ Block Section
Line Clear ↔ Authority to Proceed ↔ Block Section
Gateman ↔ Level Crossing ↔ Level Crossing Gate
Goods Train ↔ Material Train ↔ Mixed Train
Kavach ↔ Loco Pilot ↔ Regular Train Operating Rules
Studying these concepts as linked groups is particularly useful for Operating LDCE conceptual and descriptive questions.
Important Update for Candidates
Older G&SR books may show the traditional sequence directly from Definition 28 to Definition 29. Current official Railway material records the insertion of Definition 28A – IR-ATP (Kavach) after Definition 28.
Therefore, candidates using an older G&SR book should add 28A Kavach to their study notes rather than assuming that the old 60-definition list by itself represents the complete current position.
Reference: Indian Railways (Open Lines) General Rules, Rule 1.02 – Definitions; Indian Railways (Open Lines) General (Third Amendment) Rules, 2024.
Research & Content: G. D. Pandey
