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Post by Deleted on Sept 12, 2005 20:19:59 GMT
I once read somewhere that an unfettered 1995TS will go all the way up to 90mph and possibly more when opened up - is this hyperbole, or did someone actually try this and not mess themselves?
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Phil
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Post by Phil on Sept 12, 2005 21:05:22 GMT
Who the hell is going to confess to that on this forum ikea?
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Post by Deleted on Sept 12, 2005 21:21:47 GMT
Who the hell is going to confess to that on this forum ikea? I'm not asking for a confession, I'm just curious as to how fast they can go.
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Post by Deleted on Sept 12, 2005 22:14:21 GMT
90mph seems pretty unlikely - there is no reason why Northern Line trains would need anything like that speed. I've heard that the absolute limit for any train using third rail electric traction is 100mph (for technical reasons that are beyond me).
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Post by Deleted on Sept 12, 2005 22:37:39 GMT
Max speed for third rail traction is 100mph is because of the unlikely case of the traction shoes flinging off.
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Post by Deleted on Sept 12, 2005 22:52:03 GMT
I once read somewhere that an unfettered 1995TS will go all the way up to 90mph and possibly more when opened up - is this hyperbole, or did someone actually try this and not mess themselves? Well they would certainly have no problem getting to 60 - 70 mph, so i wuldnt be surprised if they could get to 90mph.
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Post by Deleted on Sept 12, 2005 22:58:39 GMT
Max speed for third rail traction is 100mph is because of the unlikely case of the traction shoes flinging off. I always thought it was shoe bounce that prevented 100mph+ 3rd rail traction.
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Post by Deleted on Sept 12, 2005 23:01:11 GMT
I always thought it was shoe bounce that prevented 100mph+ 3rd rail traction. It probably would also increase the chance of shoes being knocked off, which would increase the chance of "gapping yourself"
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Post by igelkotten on Sept 13, 2005 1:04:10 GMT
Well they would certainly have no problem getting to 60 - 70 mph, so i wuldnt be surprised if they could get to 90mph. I am not so sure about that, actually. Modern traction control packages are built to operate within a certain designed performance profile, with maximum performance within those parameters. Thus, there are definately limitations as to what the hardware is actually capable of, even if you start fiddling with the control software. While modern trains have significantly higher amounts of power and tractive effort available as compared to older trains, most of that is actually used for increases in the accelration rates -not the top speeds. And unlike old electromechanical control systems, modern computercontrolled traction systems incorporate stingent performance monitoring, and does start to protest when operational parameters are exceeded. Thus, you will be much less likely to hear heroic stories about drivers going 125 mph between Leicester Square and Covent Garden to get home for tea, but you will also have less stories about squirrel-caged motors, burned out brake rigging and overheated wheelsets needing to be swapped out. Durign the verification programme for the C20, we did some high speed performance tests. The car itself is designed for a maximum speed of 90 km/h. During some test runs, the controlling software was modified, and some 100 km/h+ running took place. During those runs, you had a very decent rate of acceleration right up to about 80 km/h, and then OK-ish acceleration up to 90 km/h. Above 90 km/h, the acceleration rate and general responsiveness was very sluggish, and you could really notice that the train was not built to go this fast. The maximum speed ever achieved was around 120 km/h, but this was on a long, long, long stretch of the blue line. And yes, the test train had a possession of the whole blue line during those runnings.
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Post by igelkotten on Sept 13, 2005 1:10:06 GMT
I always thought it was shoe bounce that prevented 100mph+ 3rd rail traction. Correct. Shoes flying off can happen at most any speed if you are unlucky, but that is mostly a bolts-and-washers issue. The problem with shoe bounce is that you get an uneven supply of traction current, with lots of peaks, dips and weird harmonics in it, which is more or less murder for modern traction control systems, and not very digestible even for old electro-pneumatic ones. Arcing sure looks pretty, but it places a heavy strain on the onboard power and control systems. Likewise, it also causes a lot of wear and tear on both the third rail and the collector shoes -it is, after all, much the same as an electric welder, although even more powerful. It can cause pitting, corroding and cracking of the running surfaces, which in turn causes uneven contact, and even more arcing, and then you have a downward spiral.
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Post by q8 on Sept 13, 2005 1:25:54 GMT
During the 60's I recall both LT and the Southern conducting experiments with magnetic shoes. I believe these were extremely successful in cutting out arcing at speed. However I believe they increased the occurences of current rails being displaced. So it was swings and roundabouts again.
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Phil
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Post by Phil on Sept 13, 2005 9:03:08 GMT
Well they would certainly have no problem getting to 60 - 70 mph, so i wuldnt be surprised if they could get to 90mph. You have forgotten about the balancing speed of motors, which is designed in. Once you reach that (whatever it is) it is scientifically impossible to exceed it unless it is forced say by descending a STEEP gradient
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Post by q8 on Sept 13, 2005 9:25:16 GMT
True Phil. I remember a Southern driver once telling me that at some places you could descend a gradient faster by coasting than motoring as the motors acted as a brake.
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Post by markextube on Sept 27, 2005 21:21:54 GMT
When the 95's were introduced they were governed down a little too much and after much complaining they powers at be juiced them with a little more power. There were a few incidents of a 95 becoming gapped on the hill towards barnet. This was after comeing to a stop at a red signal but couldnt get the speed up to move off.
Anyway on the opposite end i had one unti which had a little power than most and with the down hill gradient leaving barnet i reached 72 MPH and yes it was MPH and not KMH. How i stopped it i will tell you if you ask
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Post by Deleted on Oct 1, 2005 7:03:51 GMT
Anyway on the opposite end i had one unti which had a little power than most and with the down hill gradient leaving barnet i reached 72 MPH and yes it was MPH and not KMH. How i stopped it i will tell you if you ask I did hear once when they brought the 95ts into service, one unit was on test between the Finchleys and it reached 96mph. I can't confirm this, but I was told this anecdote by a T/Op on the line
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Post by q8 on Oct 1, 2005 9:05:10 GMT
Where the hell between the Finchleys can you get to 96mph!!?? I think that may be a bit exaggerated. 96 KPH I'll accept though.
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Post by Deleted on Oct 1, 2005 10:11:20 GMT
thats approx 60mph for all you non-metric people, which is something i've tried to replicate in BVE... not easy, i could wrangle 88kmh.... (about 55mph)
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Post by Dmitri on Oct 2, 2005 14:47:20 GMT
The maximum speed ever achieved was around 120 km/h, but this was on a long, long, long stretch of the blue line. Just for the record, the maximum speed ever squeezed out of our "classic" stock is slightly above 120 km/h.
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Post by markextube on Oct 2, 2005 22:25:08 GMT
Yea i believe you could get about 96 MPH from them down hill and completely un governed. The stock is actually designed to work on a max of about 750 volts network rail voltage. This i was told by a few technicians when the stock was on test. And also they took it onto the met line and had a run there and it reached about 96 mph.
It was also tested at speed from east finchley to finchley central with camers underneath to video movement etc. That reached a v good speed also
The only probelm with these trains is that the brakes are only as effective as the speed it is governed to. So when its ungoverned the braked copensate and can stop the train in the usual way. This i found a out a few times when going above the governed speed. You can stop it but have to be careful how and how soon!
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Post by q8 on Oct 3, 2005 8:48:03 GMT
It was also tested at speed from east finchley to finchley central with camers underneath to video movement etc. That reached a v good speed also ------------------------------------------------------------------------ I am sorry but I still dispute that. 96mph EF TO FC Nah...can't be done. Distance alone precludes that. Some is either winding you up or telling porkies.
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Post by trainopd78 on Oct 3, 2005 9:52:48 GMT
That was quite a run from FYC to EFY. Around 3 to 4 mins run time. However I reckon for a speed run is High Barnet to Totteridge. 59 stocks could do 55mph down there!
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Post by q8 on Oct 3, 2005 15:06:28 GMT
I am not calling anyone a liar here. I just dispute the fact that it is possible to get to 96mph EFY to RYC even given it may be a 3+ minute run.
However Barnet to Totteridge IS a possibility
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Post by Deleted on Oct 3, 2005 22:22:59 GMT
The maximum speed you can get from a parallel connected motor is when the emf (voltage to you) it is generating is the same as the rail voltage. When it goes faster it will then be feeding current back to the rails, and taking energy from the wheels to do it. That at least is true for old fashioned commutator/brush motors. How it goes with modern brushless motors I don't know, they hadn't been invented when I was at college many many years ago. John
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Post by markextube on Oct 4, 2005 21:53:55 GMT
Ok 95 then I've seen a three car 96 ungoverned under test and i tell you i have never seen a train accelerate so fast! At the time it left after a 73' and passed it within seconds. The info on the test of the ungoverned 95's on the met and East F to F Ctl was from various sources ranging from managers to technicians who had taken part in the testing. It is quite a good distance down hill and the fast acceleration can definatly push it up to at least 85mph i would say. As i reached 75 mph Barnet to totteridge on a governed unit faster than that can easily be reached when ungoverned.
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Post by igelkotten on Oct 5, 2005 0:52:10 GMT
The maximum speed ever achieved was around 120 km/h, but this was on a long, long, long stretch of the blue line. Just for the record, the maximum speed ever squeezed out of our "classic" stock is slightly above 120 km/h. I'm not surprised at all. After all, old-style DC-DC traction packages and motors simply continue until the back EMF stops, or the motor windings come loose, whichever comes first. Whereas, on the other hand, a modern asynchronous traction package is built for an operational envelope, and does not have much in the way of performance outside that.
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Post by Deleted on Nov 12, 2005 1:58:00 GMT
Barnet to Totteridge. 59 stocks could do 55mph down there! Was that the most a 59 could do? Also were 72's similar?
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Post by Deleted on Nov 15, 2005 18:42:31 GMT
Anyway on the opposite end i had one unti which had a little power than most and with the down hill gradient leaving barnet i reached 72 MPH and yes it was MPH and not KMH. How i stopped it i will tell you if you ask [/quote] u havent actually told us how u stopped it.... i'd be very interested as to how, even if no-one else apparently else is!! ;D
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Post by dotmatrix on Oct 7, 2006 11:04:45 GMT
thats approx 60mph for all you non-metric people, which is something i've tried to replicate in BVE... not easy, i could wrangle 88kmh.... (about 55mph) I can manage about 70 mph in BVE, but that's passing stations, and continuously delaying the tripcock, but i think those reflect the slightly exaggerated 95ts.
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Post by Deleted on Oct 9, 2006 17:46:26 GMT
thats approx 60mph for all you non-metric people, which is something i've tried to replicate in BVE... not easy, i could wrangle 88kmh.... (about 55mph) I can manage about 70 mph in BVE, but that's passing stations, and continuously delaying the tripcock, but i think those reflect the slightly exaggerated 95ts. So you ressurected a thread that is over a year old just to post some stuff about what you can do in BVE? I think you need to have a read of the forum charter.
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Post by Deleted on Oct 9, 2006 18:19:50 GMT
well said mso mind you i think BVE is a heap of garbage !! you cant beat the real thing :-) :-)
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