HSTEd
Veteran Member
- Joined
- 14 Jul 2011
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As all the long timers in this forum will know, we regularly get threads regarding double decker trains - especially when some politician or other touts them as a solution to capacity problems.
The following arguments are often cited against conversion to GC gauge or GB+ to utilise standard european double deck stock:
One thing that I have not often heard suggested, is that we could develop a specialist loading gauge that would be identical to the British loading gauge as far high as the cantrail, and would then simply continue upwards for a much larger distance, likely terminating with a flat roof more compatible with modern rolling stock design practices.
This would have significant advantages over a conversion to a continental style loading gauge:
So in other words - although the vertical clearance is extreme there are actually relatively few bridges per mile on the network as a whole, and the only real problem is that electrification equipment would have to be rebuilt.
And since the ECML is going to have lots of structures replaced anyway......
But it's just a thought.
The following arguments are often cited against conversion to GC gauge or GB+ to utilise standard european double deck stock:
- The loading gauge is wider below the platform level and thus would require massive platform works, and likely dedicated platforms
- The low floor on the lower deck would prevent gangways being provided on both decks, and would prevent a flat lower deck, and would thus inhibit disabled access and loading operations
- The vast majority of the cross section of the loading gauge would be filled with passenger accomodation or with equipment like bogies, rendering it difficult to find space for traction gear without sacrificing train length
- In addition to platforms, large amounts of equipment adjacent to the track might have to be moved, and massive painstaking reclearing works would be required
One thing that I have not often heard suggested, is that we could develop a specialist loading gauge that would be identical to the British loading gauge as far high as the cantrail, and would then simply continue upwards for a much larger distance, likely terminating with a flat roof more compatible with modern rolling stock design practices.
This would have significant advantages over a conversion to a continental style loading gauge:
- The loading gauge would be identical to traditional British practice below platform level, and can thus use the same platform structures as conventional platforms
- Conventional gauge self powered trains would be able to use large gauge lines with no modifications, and electric trains would only require an extended travel pantograph
- Once you commit to a new custom loading gauge, there is little reason to restrict the vertical clearance to the ~4700mm of the GC gauge, which in any case would not be sufficient to enable a second deck above the normal height one. In any case selecting the largest possible height compatible with stability would enable expanded freight operations - 6150mm
- As stated above, a clearance of 6150mm would enable expanded freight operations - for example double deck container operations on cleared lines. Drastically increasing the number of containers that can be hauled in a path - an important consideration on the British railway, and potentially drastically reducing costs by increasing attainable train weight.
- Virtually all lorries commonly used [Motorways are only built for ~5m vehicles in any case] on public roads could be carried on standard flat wagons, permitting rolling highways and piggyback trailer operations to be conducted far more easily and cheaply than elsewhere. This would enable railways to help reduce HGV journeys more effectively than conventional intermodal operations.
- As there would be no difference from traditional loading gauge below the cantrail, far fewer modifications would be required, especially outside of large cities where there are only relatively few overbridges and tunnels.
- The maximum cant permitted on the railway is only roughly 150mm, which translates to a tilt of six degrees, which translates to a track overhang of 610mm. Roughly 300mm more than in traditional lines. This is only a single foot and it is likely that most curved track sections would easily meet this specification without modification.
- Trains would have level lower decks, and would be gangwayed (inside the unit) on both decks, this would permit far greater lateral movement through the train and would remove many of the disadvantages seen in continental double deck trains. For example only one toilet (the disabled one) would be provided on the lower deck of a train regardless of length, all others would be on the upper deck, along with lower passenger-density areas such as catering bases, first class and similar.
- Full width cabs could be provided on the upper deck, permitting gangwaying between units on the lower deck without sacrificing driver comfort and visibility
- As the lower deck would be at the same level as traditional trains, double deck units could operate in multiple with existing classes of single deck units as required. And traction gear could be positioned below the floor the train, as on exisitng rolling stock
So in other words - although the vertical clearance is extreme there are actually relatively few bridges per mile on the network as a whole, and the only real problem is that electrification equipment would have to be rebuilt.
And since the ECML is going to have lots of structures replaced anyway......
But it's just a thought.
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