Bracamonte Posted November 12, 2010 Share #1 Posted November 12, 2010 Today I was on a New Haven Line train heading back to GCT from New Haven. As I was looking at left window and when we passed Fordham, the train generated a huge third rail arc that sprayed sparks throughout the tracks. It caused the doors to shake which scared the heck out of me. Is this common in Fordham? I have never seen an arc that big before. Link to comment Share on other sites More sharing options...
Joe Posted November 12, 2010 Share #2 Posted November 12, 2010 As long as you don't see any catenary arcs in Fordham... Link to comment Share on other sites More sharing options...
metsfan Posted November 12, 2010 Share #3 Posted November 12, 2010 Maybe a fresh pickup section on the end of a stretch of 3rd rail? - A Link to comment Share on other sites More sharing options...
N-Trizzy2609 Posted November 12, 2010 Share #4 Posted November 12, 2010 Either someone wet the third rail or the shoe on your train was a little faulty. I always seem to get M7 on the LIRR or Subway train with faulty 3rd rail shoes. They're not as dangerous as it sounds but you get a light show in the tunnel or at night. Link to comment Share on other sites More sharing options...
w8Hou Posted November 13, 2010 Share #5 Posted November 13, 2010 its a feature of the train cars Link to comment Share on other sites More sharing options...
gregorygrice Posted November 17, 2010 Share #6 Posted November 17, 2010 The M2/4s are just old. They're showing their anger towards CDOT and the MTA:p Link to comment Share on other sites More sharing options...
St Louis Car 09 Posted November 17, 2010 Share #7 Posted November 17, 2010 The M2/4s are just old. They're showing their anger towards CDOT and the MTA:pThe M4s are still a bit young.Circa 1987-1988 Link to comment Share on other sites More sharing options...
gregorygrice Posted November 17, 2010 Share #8 Posted November 17, 2010 The M4s are still a bit young.Circa 1987-1988 They're still mad though:p Link to comment Share on other sites More sharing options...
metsfan Posted November 17, 2010 Share #9 Posted November 17, 2010 Faulty shoe will fall off or fail to contact or fail to spring up onto/under the 3rd rail, in this case usually the shoe will be pushed off by the 3rd rail, but this is a major event and the train will go OOS to prevent further damage. Failure to contact could create an arc theoretically, but it would create a "running arc" till the contact surface is so charred it stops conducting. Most likely it was a new fresh section of pickup rail, those always arc pretty good, even in the most subdued 3rd rail applications. - A Link to comment Share on other sites More sharing options...
rtetro Posted November 17, 2010 Share #10 Posted November 17, 2010 This brings up a technical question. Obviously, the third rail runs at about 600 volts DC. Does anyone know what the maximum current draw is of a train at start up as opposed to running speed? I was once told by an Metro-North tech that he believed the current at 600 Volts could be as high as 10,000 Amps at start up. This computes to 6 megawatts of power (600V X 10,000 Amps = 6,000,000 watts), which seems a bit excessive. Link to comment Share on other sites More sharing options...
Joe Posted November 17, 2010 Share #11 Posted November 17, 2010 Very good question. A single R9 (running on 550V trolley and using two GE 714 motors) has a starting current of about 500A. I have no idea what motors M2/4/6 equipment uses but I do know that M3s use GE 1251 motors. Four motors total, two per truck...wired like a SMEE. For the sake of argument, we'll say that one M3 car draws 800A (more efficient motors), figure ten car train...800A*10 = 8000A. Doesn't seem too far off. Link to comment Share on other sites More sharing options...
Messino Posted November 17, 2010 Share #12 Posted November 17, 2010 its more like 5,000 amps max that is supplied via the 3rd rail. And I believe its only 100 amps at startup Link to comment Share on other sites More sharing options...
Joe Posted November 17, 2010 Share #13 Posted November 17, 2010 its more like 5,000 amps max that is supplied via the 3rd rail. And I believe its only 100 amps at startup Haha, no. 100A? Is that some sort of a joke? Link to comment Share on other sites More sharing options...
Messino Posted November 17, 2010 Share #14 Posted November 17, 2010 Haha, no. 100A? Is that some sort of a joke? I dunno, thats what a t/o told me a while back Link to comment Share on other sites More sharing options...
Joe Posted November 17, 2010 Share #15 Posted November 17, 2010 A lot of the T/Os these days suck at moving trains...like they know anything about what makes them move... Link to comment Share on other sites More sharing options...
rtetro Posted November 17, 2010 Share #16 Posted November 17, 2010 What made me think about it is that my 50,000 watt AM transmitter at work operates with a supply voltage of 230VDC and draws about 217.5 Amps with no modulation. (With modulation it pumps up to about 300 Amps.) I assumed that a 8-10 car train would require much more current than that. Perhaps the MN tech I spoke to was not too far off. I need to see if I can find some on line specs for the motors. Link to comment Share on other sites More sharing options...
Joe Posted November 17, 2010 Share #17 Posted November 17, 2010 If you manage to find any specs for GE 1251s, do post. If you can get overall specs on M2/4/6 equipment, even better. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.