Central Railway has Introduced an Innovative OHE Parameter Measurement Gauge for Swift Inspection & Early Fault Detection of OHE
Central Railway (CR) has introduced a groundbreaking OHE (Overhead Equipment) Measurement Gauge designed in-house. This instrument aims to revolutionise the assessment of OHE parameters, with a specific focus on turnouts, crossovers, and overlaps. The design is developed in-house by the Kurla OHE Depot, central railway technical team.
Why & How is the OHE Measurement Gauge developed by CR important?
One of the most critical aspects of railway infrastructure is ensuring the standard OHE parameters at points and crossings at all times. Deviations in the standard parameters of Crossovers and Turnouts have historically led to Pantograph entanglements, resulting in significant disruptions in traffic flow. For instance, Height and stagger of the contact wires are the main parameters to be monitored at crossovers and turnouts.
Additionally, the non-availability of Traffic and Power Blocks due to dense suburban and mail/express traffic for checking Crossovers and Turnouts by Tower Wagon has posed considerable challenges.
Therefore, the OHE Measurement Gauge has come as a boon as it –
- Eliminates Need of Traffic & Power Blocks and Prevents Detention of Services
- Minimises Use of Tower Wagons and Labour Power for OHE Inspection
OHE Measurement Gauge – An Innovative Solution
- The OHE Height, Stagger, and Implantation Measurement Gauge uses advanced laser-based technology to measure accurately without physical contact.
- Railway personnel can efficiently conduct live line checks and monitor them using a user-friendly mobile app with GPS mapping features.
Key Benefits of the OHE Parameter Measurement Gauge
Accurate mapping of contact wire height and stagger on the main line and at crossover points, with GPS tracking and PDF reports.
- Precise measurement of contact wire height differences at critical points without touching.
- Fast, safe, and precise OHE measurements using modern laser tech.
- Automatic stagger adjustment based on track slope.
- Lightweight and easy to handle.
- No need for traffic and power disruptions during operation.
- Reduced staffing needs, requiring only 1 to 2 personnel.
- Quick measurements, with each location taking just 5 to 10 minutes.
- Cost-effective setup, with each gauge priced at around 1.2 lakhs only.
What Motivated the Central Railway Engineers?
The challenges posed due to the dense traffic and the commitment towards maximising service hours motivated the central railway engineers to develop the instrument.
The Mumbai Division is India’s busiest, featuring 1810 suburban and 250 mail/express services over a 555 km network. It has 4 to 6 lines in the CSMT-KYN Section and 2 lines in other sections.
- Each line individually has a 3-hour night block margin for routine maintenance.
- However, crossovers and turnouts require a joint 2-line block, lasting only 1 hour, which is insufficient due to differing train movement timings.
- Combining 2 lines (e.g., Up & Down Slow lines) also provides only a 1-hour block margin, inadequate for maintenance.
Currently, 1 OHE measurement gauge is operational, with plans to deploy 70 more in the next 4-6 months.
Below sections will give the readers a brief on the defects that cause disruptions in the rail traffic.
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What is Pantograph Entanglement?
Pantograph on a rail is a system that is mounted on electric locomotives whose main function is to draw power from the suspended electric lines and transfer it to the electric locomotive. So, to make sure the locomotive runs smoothly, the pantograph should move freely along the contact wire without any obstructions.
Pantograph entanglement occurs when something goes wrong either with the overhead equipment (OHE) or the pantograph itself. Sometimes, entanglement can happen during accidents or rough weather, like storms. When the pantograph gets entangled, it damages both the pantograph and the overhead equipment, which disrupts electric train services.
Once pantograph entanglement occurs, it becomes quite challenging to figure out whether the problem started with the OHE or the pantograph itself. It takes a lot of effort to determine which one failed first.
Reasons for Pantograph Entanglement
Pantograph entanglement happens for a few reasons:
Damaged OHE components like insulators, tubes, jumpers, and droppers can get in the way of the pantograph and cause entanglement.
- Common OHE defects leading to entanglement include:
i. Not setting the wires correctly at turnouts or crossovers.
When the stagger (the horizontal positioning) and the height of the contact wire at a turnout or crossover are not set correctly, it can lead to the pantograph getting tangled with the overhead wire while the locomotive is moving on the main line.
ii. Problems with the auto tensioning device (ATD) that keeps the wires at the right tension.
The Auto Tensioning Device (ATD) keeps OHE wires at the right tension. If the ATD drum is stuck, the wires may sag in hot weather and break in the cold. Sagging wires can entangle the pantograph, especially at high speeds. Proper ATD function is essential to prevent these problems.
iii. Failures in the joints of the contact wires.
The contact wire has joints along its length, which are made during manufacturing. If these joints fail, it can cause the contact wire to snap or break.
iv. Damage to OHE components like insulators.
Damaged OHE components like insulators failing due to corrosion or flashover, fixtures coming loose, PG clamps, splices, bolts, and similar issues can also lead to pantograph entanglement.
- Pantograph problems can also lead to entanglement.
- Common pantograph defects include:
i. Failure in the spring box.
ii. Incorrect static forces on the contact wire.
iii. Missing pins and fasteners.
iv. Cracks in mechanical parts.
v. Base insulator bolts coming loose.
vi. Pantograph pan not being level.
Sometimes, things outside of the pantograph and OHE system can cause entanglement.
i. The overhead wires move because of wind or storms.
ii. Objects like birds or monkeys hitting the overhead wires.
iii. Tree branches or foreign objects on the wires.
iv. Theft of materials.
v. Changes in the track’s alignment and level.
These are the main reasons why pantograph entanglement can happen. It’s important to check and maintain the OHE system and the pantograph to prevent these problems.