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Keeping our cool

Air conditioning is a crucial component in keeping commuters cool on the train. Nothing irks us more than hoping to escape the humid Singapore weather by taking the train, only to find it stuffy and warm.

On all North-South and East-West Line trains, there are two air conditioning units per train car. With six cars making up a train, that’s 12 air conditioning units working keep the temperature within the train cool. There are 141 trains for the NSEWL, that’s 1,692 air con units! Excluding those undergoing maintenance on the workshop floor.

So how does SMRT maintain the air conditioning systems on the trains to help you keep cool and carry on?

keepcool

Here are some top reasons for aircon failure according to a recent analysis on data collected from December 2015 to February 2016.

Blown Fuses in the aircon motor

SMRT Technical Officer Hairul Bin Seradeen inpects the aircon unit for defects

SMRT Technical Officer Hairul Bin Seradeen inpects the aircon unit for defects

 

One of the most common reasons for failure was the aircon system fuse. A blown fuse indicates excessive current which could be a result of arcing caused by the carbon dust build up inside the motor.

The source of the carbon dust is the carbon brush, a component in the aircon unit that is in contact with the aircon motor. Through normal operations, the carbon brush is wears down and carbon dust settles on the motor.

A more effective cleaning method to remove excessive carbon dust build-up has been implemented and new carbon brushes are being trialed to reduce the carbon build-up in the long run.

Defective Microcards

Microcards are like the brains of the aircon unit. When there is a defective microcard, the aircon no longer functions the way it is supposed to. In some situations, the unit fails to activate when temperatures get too high.

While replacing the defective microcards with new ones from the manufacturer is one solution, SMRT has been working on a more sustainable solution. The Integrate Electronics Workshop team at SMRT have studied the microcard and have been refurbishing defective microcards.

Leaky tubing

Freon topping up machine

The trains’ aircon units use a gas known as Freon as a refrigerant which cools the air. The Freon gas cycles within the unit in a closed system of coils. If the Freon leaks from these coils, cooling efficiency is reduced. We are stepping up efforts to plug leaks in these tubes though a process known as “brazing”.

The Freon also needs to be topped up when leaks are discovered. The use of a recovery machine ensures that the precise composition of refrigerant is used to ensure cooling efficiency.

 

 

 

Keeping an eye on things

The later models of trains on the NSEWL (KNS and KSF) are all equipped with the Trains Information Management System, or TIMS. TIMS is an entire system of sensors that measure various properties of the train during operations. The internal temperature of each car is one such property.

SMRT on board monitoring

During service, train captains can check TIMS for any aircon faults. When faults are detected, a “field team” is activated. The team will then verify the fault and where possible, rectify the issue immediately. Further inspections to the reported aircon system will also be carried out when the train returns to the depot.

SMRT Condition Monitoring Technologies

The North-South and East-West Lines (NSEWL) are two of Singapore’s oldest heavy rail lines. These lines carry almost 2.5 million passengers from as early as 6am to around midnight each day.

 

The Challenge

Maintenance teams have only a few hours each night to rectify any infrastructure faults that may cause interruption to train service the following day. Relying solely on the human eye to discover faults across the 200km length of track on the NSEWL would be like searching for a needle in a haystack.

SMRT_Train_Perspective

How do we overcome these challenges?

It was thus important for SMRT to develop a suite of condition monitoring systems to properly observe and gauge the status of the track and other components in the network, enabling maintenance teams to better plan maintenance schedules and priorities.

Multi-function Vehicle (MFV)

Multi-function Vehicle (MFV)

SMRT has been building its capabilities with condition monitoring technologies as early as 1995, with the introduction of the Multi-Function Vehicle (MFV). The MFV can scan long stretches of track, if not the entire line, to collect data that relates to track geometry, rail flaws and other measurements.

In this series of blog posts, we will introduce the rest of the condition monitoring technologies and how they help our maintenance teams.

 

To start off, here are ten quick facts about Condition Monitoring

# 1: Linear Variable Displacement Transducer (LVDT) was introduced in 2013

# 2: LVDT is also referred to as Third Rail Sag Detection System. It monitors the overall alignment of the power providing third rail.

#3: RailVision was introduced in 2009 and uses a combination of image capture and detection systems to identify faults on a track.

#4: RailVision is able to cover the entire NSEWL in a matter of hours. It would have taken days for patrol teams to cover the same distance.

#5: Multi-Function Vehicles (MFV) were first introduced in 1995 and has since been evolved under the Engineering Trains Branch team.

#6: MFV use other systems, such as one that utilises ultrasound technology, to detect rail condition.

#7: The Laser Trolley is one of the newer conditioning monitoring devices. It was introduced last year, in 2015

#8: In order to measure both rails at the same time, the Laser Trolley had to be customized according to SMRT’s specifications.

#9: The small rocks that the tracks rest on are known as the ballast and they have to be monitored as well.

#10: The conventional way for checking the ballast is to dig out and send samples to labs for testing.

Follow our series on Condition Monitoring as we go deeper into each condition monitoring device.

Trains services at 13 North-South East-West Line stations to start an hour later on Sundays

From 5 June 2016 to 18 December 2016, train services at 13 stations along the NSEWL – Joo Koon to Queenstown on the East-West Line (EWL) and Bukit Gombak to Jurong East on the North-South Line (NSL) – will commence service up to one hour later than usual on Sundays, except on public holidays. Train services at these stations will start by 7am.

Currently, our project teams, track patrol teams and maintenance teams have about three to four hours of engineering hours each night to carry out works to renew and upgrade the system, in addition to carrying out regular maintenance needed for daily train operations. The later opening will enable these teams to gain the equivalent of 29 additional maintenance nights over the 6-month period. This translates into 2,320 more sleepers and an additional 3,230 metres of third rail that can be replaced. The EWL sleeper replacement project is on track for completion in early 2017.

Alternative travel arrangements
Commuters are encouraged to plan their travel to start after 7am on Sunday mornings where possible. For commuters who must travel before 7am, they can use the existing bus services to get to other train stations; or use the Circle Line and Downtown Line to get to the city. SMRT has also arranged for a new parallel bus service to ply the route from Joo Koon to Bukit Gombak in both directions. More information of the new parallel bus service and fares will be made available within the next few weeks.

EWL sleeper replacement work has reached 50% mark
To date, SMRT has replaced half of the 92,000 timber sleepers on the EWL with more durable concrete ones. This steady progress is made possible by the additional 30 minutes every night that our engineers have gained from early closure of some EWL MRT stations since November 2015.

Apart from sleeper replacement, SMRT is also carrying out other rail renewal projects such as third rail replacement and re-signalling along the NSEWL. While the various parts of the track are being renewed, track patrols and maintenance work will continue. The various project teams, track patrol teams and maintenance teams compete for the limited engineering hours available every night between the end of service and the start of service the following day. To accommodate the track access necessary for the engineering teams to carry out these works, SMRT will commence train services at the western sector of the NSEWL up to an hour later every Sunday.

Progress of multi-year, multi-project rail renewal programmes

This is the progress of the multi-year, multi-project rail renewal programmes on the NSEWL as at 12 April 2016:

SMRT - Progress on Rail renewal programmes

Rail renewal works to be carried out safely and in the shortest time possible

Managing Director of SMRT Trains, Mr Lee Ling Wee, said: “Our priority is to ensure rail renewal works are carried out safely and in the shortest time possible to improve rail reliability. Extending our limited engineering hours by an additional hour once a week allows our engineers to gain additional track access to work on their respective projects and carry out maintenance work. All this is done while trains continue to run and serve commuters every day. We seek the understanding and patience of commuters and the general public as we do our very best to complete the various renewal programmes with minimal impact to our train services.”

Commuters are advised to check for travel updates before starting their trip. Information will be available on the SMRT website, SMRT Connect, LTA and SMRT Facebook and Twitter accounts, LTA Traffic News and MyTransport.SG.