Originally posted by kitoshizc:
Some queries here..
1) Today while waiting for Punggol Train at Kovan Station, after the last train departed the platform, few mins later, another train, not in passenger svc, went past the same platform.. Anyone knows where it is heading? Or will it jus park at a station??
2) After last train at Punggol, they will jus go back to depot straight? Where's the track that leads to the depot? Do they go to sleep automatically after reaching depot?
3) Anyone has any pictures of the train operations like depot operations??
4) Wat time do they wake up and sleep?
Thanks
1. Since you are waiting for a train to Punggol, and the last train has left, I suppose what you are referring to is that the last passenger service train has left the platform towards HarbourFront. Now, it is known that after the last passenger service train left for HarbourFront, there will be a yellow maintenance locomotive that will follow it, which I suppose came out through Sengkang North crossover, north to Punggol and back south. What it does is to move along the track and detect for areas where there are rail faults, due mainly to over-grinding (at bends) and so.
You will be surprised that our wheels on MRT systems here are changed once in a few months, at most a year, due to wear and tear, and the track is also facing the same type of operational stress during operation.
Back to this locomotive. It will go all the way to HarbourFront, then back to Sengkang Depot by Buangkok south crossover. It may stop for a while at stations, but that is due to it being too close to the last train in front of it.
2. Every train, when it has completed its scheduled service, will pull out of the main tracks back to the depot. This is necessary to prevent disruption to normal service.
There are 2 crossings (for changing tracks) leading to Sengkang Depot. The Buangkok South entrance can easily been seen when you take a NEL train northwards towards Punggol. It is located just before reaching Buangkok station, a crossing branching out to another tunnel on the left.
The Sengkang North entrance can be seen when you take a NEL train southwards towards HarbourFront. It is located just after the train left Sengkang for Buangkok. Sengkang has 2 single-nose crossings for changing between the north and south-bound tracks, and these are placed closest to the station. There is a 3rd and 4th single-nose crossing connecting a middle tunnel and both the North and the South tracks. This middle tunnel leads to Sengkang depot. To locate the tunnel, look out for the tunnel led by the 3rd crossing after a train has left Sengkang. You should be able to catch only a glimpse of it. The tunnel then moves higher above the HarbourFront tunnel, as noted by the HarbourFront tunnel moving lower and to the left towards Buangkok.
The crossing connecting Sengkang North entrance and northbound tracks is the first crossing after leaving Buangkok for Sengkang. Now you know why the whole Sengkang crossing area is so long.
Trains go to sleep after the trains' operating system has done a check with all the components in the train, like power intake, back-up power, communications systems, doors etc. Just before a train goes to sleep, its will lower the "intaker" on the top of the train away from the overhead electricity cables. For your information, the overhead cables is the positive pole and the third rail (white, next to the 2 rails of the track) is the negative pole, whose potential difference is 1500V DC.
Cleaning is done at HarbourFront. At various periods of the day, cleaners board the train at HarbourFront after passengers have alighted. In the few minutes where the train rests at the overlay tunnel behind the station while waiting to cross-over to the other platform, cleaners do a quick job of spricing up the cars.
3. You can try SBSTransit website.
4. Trains wake up automatically at 5am and does a through self-test again to ensure all components are working. Trains that failed the test will not go into passenger service. After downloading the day's schedule and accorded the respective Train Run Number (TRN), which is something like duty codes (NEL uses 301-325 for passenger service trains), they are ready to set off. Adhering to the schedule, they will then set off. The Operations Command Centre's (OCC) computers will also make sure the crossings are correct so that the train can move out in time.
As for the computer systems, SMRT do have many computer systems in place too, but they do more of an advisory role. Some systems in use by SMRT are Automatic Train Operation (ATO), Automatic Train Protection (ATP) etc. Similar systems are employed by NEL and most modern rail systems around the world.
Automatic Train Protection (ATP) is in charge of ensure collisions do not happen and trains keep a safe distance from each other. Behind every train, ATP sets a increasing speed limit for every track sector as the distance increases. A train behind, when coming too close to a train will sound a buzzer and automatically slow down to the speed limit defined for that track sector to prevent a collision. Another type of speed limit tied to track sectors is influenced by the default speed limit set for the track, like a lower speed for a downhill section, rain or construction cranes near tracks. A driver who forgot to slow down the train will upon reaching it will have the train sound a buzzer. However, since this is usually not a dangerous situation requiring immediate action, the train is not automatically slowed down and the passenger train operator (PTO) will pull the throttle to slow the train down.
Note that while ATP has ensured the safety of train operations, it has failed before. The most famous example is the train crash at Clementi station in the late 80's. A train from Ulu Pandan Depot came out and parked at Clementi westbound platform. However, ATP failed to prevent the westbound train from (then) Buona Vista from approaching Clementi station and it is up to the PTO to see a train in the station and e-braking his train to prevent a disaster. The train crashed into the stationary train, but at a very low speed such that there was actually not much physical damage but standing passengers were jolted out of their positions and fell since there is still the collision happening. However, ATP has been accurate thus far, and LTA has required 98% of the track signals (which is controlled by ATO but partly affected by ATP) to be correct in SMRT"s annual audit.
ATO is in charge of signalling and communcation systems, which inform the driver whether he should proceed beyond or stop at certain points through red or white lights. This is not to be confused with the term Automatic Mode (AM) employed by NEL.
Crossing signals are used to inform a driver whether the track is set to the correct direction where he wants to head to (the destination codes, which are same as station abbreviations like MRB, JUR etc must be set by PTOs before departing from a terminal station and of course this destination information will find its way to VPIS at stations' plasma TVs). This is especially important at terminal stations during peak hours where it's likely that a train had just crossed over to another track and the machine at the crossing has not adjusted the crossing back to the direction required by the oncoming train, which happens as the headways are short like 2 mins per train.
Station signals are used to inform a driver if he can proceed beyond the station. This information is affected by scheduling and ATP. If a train has arrived at a station early, he will not be permitted to go beyond the point. In the event that a train goes beyond the station illegally, ATP will cause the train will halt on its own and OCC notified. The PTO can then speak to OCC to override the signal setting if OCC officers allow (they can see every train in the network and can tell if there is indeed no problem with proceeding).
More about operation modes of trains. Trains usually run in 3 modes: Automatic Mode (AM), Control Manual (CM), Restricted Manual (RM). AM is employed solely by NEL trains. There is some speculation that the new Kawasaki Nippon Sharyo black trains can use this mode too. CM is employed by SMRT PTOs for everyday normal train operations. The PTO takes full control of the train while the computer systems continually assesses the train's safety distance and operations and advises the driver accordingly, with the possibility of intervening when the situation requires it. NEL trains can be set to CM too, that is, the customer service officers take over the control of the train. CM is a common rail operation term, and it is also listed in the NEL train's driver console LCD as one of the options. Selecting it will allow you to take over the train. RM is used only when there is some major problems that require the train to move at very low speeds, like using a train to couple a stalled train back to depot. Manual controlling like CM is possible, but some functions are disabled and the speed limit is there.
The NEL computer systems generally uses Windows 2000 with on-the-shelf components, things like modem cards that you use on your computer. However, the entire computer network is private and that is the only thing that prevents intruders. Don't fret however, as our ATM machines are Windows NT or 2000 machines too. That's why there were news of ATMs in USA getting virus attacks like the one spread through the Internet. for some reason, their network was connected to the Internet. whether this is a loophole or they tried to use SSL or VPN over Internet to save costs is not sure though.
some old stuff about NEL:
http://www.sgforums.com/?action=thread_display&thread_id=69193&page=3
