South Western Railway and Network Rail - merged posts

[whole diary]

[bradshaw]

I feel that this scheme should be looked at as part of a long term future full electrification strategy, not just in isolation.
There must be a fairly good case for electrifying from Southampton to Reading via Salisbury and Basingstoke for the freight route to and from Southampton. If so then this, in all likelihood will be at 25Kv OHLE. Likewise from Yeovil to Exeter might have to be considered as part of the GWML^▸ (Great Western Main Line) diversionary route as well as the Devon Metro.
Thus the scheme chosen for the Basingstoke to Exeter line should be able to sit within this not just in isolation.
However, I wonder if the current thinking is along the lines of charging as on the Greenford branch, which appears to be progressing well. If so then sections of charging rails will be in stations, perhaps Salisbury, Yeovil, Axminster and New Yard, Exeter. This might be backed up with short sections of third rail where current drain is heavy, such as Sherborne, Honiton and Crewkerne banks.

[broadgage]

Short sections of conductor rail for charging a static train in a platform should be acceptable to the healthansafety as they could be fitted with an interlock so as to be dead except when a train is parked over them.

I remain very doubtful about all but trivial extensions to conventional conductor rail systems for reasons already given.

25KV is the future especially if heavy freight or full length, fast passenger trains are expected.
Lightweight tramway style overhead at 750 volt DC^▸ (Direct Current) is worth considering for local passenger services.

[infoman]

As the article is behind a pay wall,

would anyone like to hazard the cost of the 125 miles if the construction started today?

[bradbrka]

The key points taken from the printed version of the article in Rail are

Modified Class 450 or 701 trains, batteries put into space that transformers would occupy if they were 25kv fitted.

15 third rail islands concentrated in areas of rapid acceleration such as stations.
 
Total 50 miles third rail.

Suitable electric connections identified avoiding needing very high voltage grid points.

Based on the above, islands would be approx. 3.3 miles long averaging 8 miles apart. Station spacing between Basingstoke and Honiton varies between 4 to 13 miles so would fit with the above. After Honiton they are more closely spaced so would not all need third rail.

[Electric train]

So, at line speed, how many miles of third rail would be required how often to keep the b attery at least 75% charged? Or is that answer impossible?

Once at line speed trains require very little energy to keep them going due to the very low rolling resistance

Third rail

I doubt that it will be allowed.
Someone, somewhere, will have to "sign off" the design as being as safe as is reasonably practicable, whilst knowingly rejecting safer alternatives such as OHLE, or batteries throughout. That person could be at risk of criminal prosecution, maybe decades later, when a trespasser is electrocuted.

The ORR^» (Office of Rail and Road formerly Office of Rail Regulation - about) have not ruled out top contact third rail on new electrification. 

There are a number of constraints, improved fencing, NR^» (Network Rail - home page) to look at the risks in station areas for which a scheme has been developed for station platform areas for the power in the conductor rail to be off when not required by trains.  The main point the ORR want to see is management of the electrical risk to the general public and staff