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| Thread ID: 93836 | 2008-10-02 20:35:00 | How To Save Recources When Building An Electric Railway | Roscoe (6288) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 709373 | 2008-10-02 20:35:00 | Most people are aware of the electrified portion of the North Island Main Trunk railway line . Not to well known might be the voltage supplied to the engines – 25kV AC at 50Hz . The advantages of that system were well known and proven and considered well worthwhile compared to other systems such as the Wellington electrification that runs 600v DC . With the higher voltage a smaller cross-section is required for the conductor wires, saving a considerable weight of copper; because of their lighter weight the catenary from which the conductors are suspended, with its supports, could be lighter also . New Zealand Rail possibly made its decision to use 25kV AC from savings made in England . A 25kV AC system was chosen over 1500 DC on the 180km line from London-Euston to Birmingham and the savings were considerable: 27,000 tons of copper and 16,000 tons of steel . Also as a result of high-voltage transmission it was possible to cut from 70 to 12 the number of substations required for feeding the current to the line conductors . The distance of the electrified portion of the NZ line is 411km, nearly five times the distance from Euston to Birmingham so the savings were more than considerable . The decision to use 25kV AC has other advantages . Among them is a reduction of the current consumed compared with 1500V DC and greater reliability in the current supply . Greater freedom from surges of current makes failures of the insulation less likely and there is less risk of fire from short-circuits and damage from flashovers . With improved adhesion lighter locomotives can be used to do the same amount of work; thus the standard 3,000kw/4,000hp Bo+Bo+Bo class EF locomotives weigh only 107 tons . The information was gleaned from a British Railways publication . I found it interesting . Thought you would like to know . |
Roscoe (6288) | ||
| 709374 | 2008-10-02 20:50:00 | "Trainspotting" was a good movie... | johcar (6283) | ||
| 709375 | 2008-10-02 21:09:00 | Where is this line, and is it currently serviceable? | somebody (208) | ||
| 709376 | 2008-10-02 21:42:00 | Where is this line, and is it currently serviceable? Runs between Te Rapa and Palmerston North. It was built in the 1980s over the busiest part of the railway system. The railways bought 22 locomotives but not all are running at present mainly, I think, because of one or two accidents. The EF class electric locomotives (originally known as 30 class because all their running numbers start with 30) haul more tonnage more easily and quickly. Their take-off speed is something to witness. The most powerful diesel electrics are no match. For a brief description, have a look at en.wikipedia.org |
Roscoe (6288) | ||
| 709377 | 2008-10-03 06:12:00 | [QUOTE=Roscoe;715546] The advantages of that system were well known and proven and considered well worthwhile compared to other systems such as the Wellington electrification that runs 600v DC. QUOTE] Just a slight correction Wellington electrification runs on 1500v DC. |
tutaenui (1724) | ||
| 709378 | 2008-10-03 07:01:00 | Just a slight correction Wellington electrification runs on 1500v DC. I thought it was 600. Sorry about that, chief. I do understand that the new(ish) units are able to run on more than one voltage. Perhaps they are able to run on the 25kV North Island Main Trunk? I think so. |
Roscoe (6288) | ||
| 709379 | 2008-10-04 00:28:00 | My N gauge locos only use 12V saving much more power ! and they use much thinner copper wires. Seriously though that was quite interesting. I wonder what the latest modern practice is ? |
Digby (677) | ||
| 709380 | 2008-10-04 00:33:00 | Who knows what the poverty rock rail wizards will dream up next - - wheels? | R2x1 (4628) | ||
| 709381 | 2008-10-04 00:59:00 | I must say that I wonder what a BoBoBo is. Sounds like something you give to a baby to play with. :) | Richard (739) | ||
| 709382 | 2008-10-04 08:49:00 | BoBoBo is the wheel arrangement. On diesel electric and electric locomotives, the non-motored, carrying axles are indicated numerically, but the number of driving axles is shown by letters. In the driving wheel group, 'A' signifies one motored axle and 'B' two motored axles, etc. When the suffix letter 'o' is added to a driving axle group, it indicates that each axle has its own motor. So BoBoBo means three sets of two motored axles. Quite simple, really.:) The steam locomotives had an easier notation. The most powerful, successful steam locomotive in NZ was the 'K' class which had a wheel arrangement of 4-8-4 - it had four leading wheels (two each side) eight driving wheels (four each side) and four trailing wheels (two each side.) I say "the most powerful, successful" because there was one locomtive, the Garratt, which was more powerful but it had a short life as it was most unreliable. That was simple and painless, eh?:) |
Roscoe (6288) | ||
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