IoW light rail conversion proposed

[jim.snowdon]

1 hour ago, Christopher125 said:

The power supply isn't up to it

I'm not certain that I can see why that should be the case, unless any of the original substations have been taken out of use.

 

Jim

[Zomboid]

The power draw of a 484 might be higher than the 483s or whatever the original ones were.

 

The railway infrastructure should be capable of delivering just as many megawatts as it was originally, but it's supplied from the main island 33kV distribution, which isn't the strongest, and is probably more heavily loaded now than it was originally. So maybe the supply available for traction isn't what it was. Contractually that shouldn't be the railways problem if the agreement is to supply xMVA to each location like it usually is for railway supplies. But if the electrons aren't there it doesn't matter what the paper says, they're not disconnecting houses to run longer trains.

[jim.snowdon]

29 minutes ago, Zomboid said:

The power draw of a 484 might be higher than the 483s or whatever the original ones were.

 

The railway infrastructure should be capable of delivering just as many megawatts as it was originally, but it's supplied from the main island 33kV distribution, which isn't the strongest, and is probably more heavily loaded now than it was originally. So maybe the supply available for traction isn't what it was. Contractually that shouldn't be the railways problem if the agreement is to supply xMVA to each location like it usually is for railway supplies. But if the electrons aren't there it doesn't matter what the paper says, they're not disconnecting houses to run longer trains.

That side of things is only a problem if the railway has previously agreed to reduce its load with the electricity supplier, otherwise it is the suppliers problem to maintain capacity in the face of rising demand.

 

Jim

[Mike Storey]

Whatever, good news at least. The advantage of the Vivarail product is that more can be ordered, if needed.

[Christopher125]

4 hours ago, 009 micro modeller said:

 

Obviously the relatively large class 485/486 Standard Stock fleet provided for the original electric service would not be necessary for the kind of service planned in future, but even when the 1938 stock originally entered service on the island 9 units were refurbished for Island Line.

 

That's true but they never actually needed 9 even with the Pier Shuttle in operation and the fleet was quickly reduced  - with the D78s being several metres longer, more spacious and hopefully requiring less maintenance 5 seems a realistic number for a service that appears to have got by for 5 years (until today!) with running 2-car trains with three operational units.

 

2 hours ago, jim.snowdon said:

I'm not certain that I can see why that should be the case, unless any of the original substations have been taken out of use.

 

 

To be fair it's hard to say for sure what the situation, it's been suggested that the power supply is fragile with a significant voltage drop at Shanklin while others have refuted this - presumably the forthcoming upgrade will address any issues.

Edited September 18, 2019 by Christopher125

[Zomboid]

7 hours ago, jim.snowdon said:

That side of things is only a problem if the railway has previously agreed to reduce its load with the electricity supplier, otherwise it is the suppliers problem to maintain capacity in the face of rising demand.

 

Jim

I agree. But that doesn't mean that they have actually increased capacity in line with demand.

 

I'm only speculating though, not that familiar with the general state of the island's power supply.

[Suzie]

Perhaps a move to LED lighting and local domestic solar generation in the sunniest place in Great Britain may have made more 33KV available from the grid. This has happened in places like Orkney where the mainland connector is overloaded exporting wind power to the mainland!

[PhilJ W]

The other alternative is to fit the new stock with batteries as well as the third rail collectors to make them an all electric hybrid. It depends of course if the running cost reductions can cover the cost of the batteries.

[Christopher125]

I've just had a look at the Brinton Report and he has the following to say about the power supply:

 

Quote

As someone who was responsible for the Power Supply system in the Island in the late 1980s, I am at a loss to understand some of the statements made in the Garnett Report relating to this subject. When the system was installed it was designed to support a 12 minute frequency service of seven coach trains. Since this time there have been no changes to the system which affect the supply to the conductor rail...

 

...The sub-stations are largely as built, with only routine maintenance being undertaken on the power equipment since 1967. Some of the supervisory/control equipment has been renewed over the years due to changes in the method by which the sub-stations are controlled from the mainland based, Network Rail electrification control rooms. The HV (33kV) supplies to the sub-stations and the associated switch gear are owned and maintained by Scottish and Southern Electricity, as the local electricity distribution authority. It is my understanding that the recent power supply system failure was due to a supervisory/control issue, not the actual power side of the system.

 

Edited September 18, 2019 by Christopher125

[The Stationmaster]

I see a comment has been made already but will the D78 stock really fit the tunnel at Ryde?  This has always been quoted as the reason why C1 restriction stock could not be used on the Island.  While the D78 dynamic envelope is probably not up to full C1 dimensions the vehicles are signficantly higher than tube stock.  Does their adoption mean the line through the tunnel might be singled to improve clearances I wonder?

[TomJ]

Would singling it help? It has two separate entrances for each track. I presume it’s therefore a twin bore tunnel?

[Zomboid]

I doubt singling will help as the tunnel is two single track bores.

[uax6]

Is the tunnel twin bores? From what I've read they are twin at the entrances and a single bore in the middle.....

 

Andy G

[Christopher125]

1 hour ago, The Stationmaster said:

I see a comment has been made already but will the D78 stock really fit the tunnel at Ryde?  This has always been quoted as the reason why C1 restriction stock could not be used on the Island.  While the D78 dynamic envelope is probably not up to full C1 dimensions the vehicles are signficantly higher than tube stock.  Does their adoption mean the line through the tunnel might be singled to improve clearances I wonder?

 

Yes, being relatively short and low they fit through the tunnel - as I think I've said before 03079 was squeezed through in 1984 with it's original cab so there's more room than people assume, but clearances generally (including Rink Road overbridge and the curved platform at Esplanade) still preclude conventional rolling stock designs.

 

Gareth Dennis has tweeted about it: https://twitter.com/GarethDennis/status/1173851373185712129

 

Edited September 18, 2019 by Christopher125

[TomJ]

2 hours ago, The Stationmaster said:

I see a comment has been made already but will the D78 stock really fit the tunnel at Ryde?  This has always been quoted as the reason why C1 restriction stock could not be used on the Island.  While the D78 dynamic envelope is probably not up to full C1 dimensions the vehicles are signficantly higher than tube stock.  Does their adoption mean the line through the tunnel might be singled to improve clearances I wonder?

I know we can be pretty inept in this country sometimes but I’d like to think they’d have measured first before ordering the trains

[uax6]

1 minute ago, TomJ said:

I know we can be pretty inept in this country sometimes but I’d like to think they’d have measured first before ordering the trains

 

Sadly that's not always the case.....

 

Andy G

[PhilJ W]

2 hours ago, uax6 said:

Is the tunnel twin bores? From what I've read they are twin at the entrances and a single bore in the middle.....

 

Andy G

IIRC one end is single bore. Its quite possible that they would tweak the track alignments to ease some clearances and/or impose speed limits where clearances are tight.

[phil-b259]

1 hour ago, TomJ said:

I know we can be pretty inept in this country sometimes but I’d like to think they’d have measured first before ordering the trains

 

Erm.....

 

Grater Anglia - the Stadler units wouldn't fit through Ipswich tunnel until NR had made significant infrastructure alterations

 

SWR - The Power Supply system cannot deliver enough current to the conductor rails to support the enhanced timetable which won First group the franchise.

 

With the current trend of the DfT / HM Treasury obsessed with micromanaging the railways (though always hiding behind TOcs, NR, the ORR, etc.) nothing much surprises me these days!

 

 

 

[Christopher125]

23 minutes ago, PhilJ W said:

IIRC one end is single bore. Its quite possible that they would tweak the track alignments to ease some clearances and/or impose speed limits where clearances are tight.

 

The tunnel is twin single-track bores at each end, with a double-track bore between them.

 

Mostly arched apart from a short covered-way under the esplanade roundabout; that end also features quite a sharp reverse curve which also impacts gauging for long/wide/tall vehicles.

 

Edited September 18, 2019 by Christopher125

[RichardLong]

2 hours ago, Christopher125 said:

 

The tunnel is twin single-track bores at each end, with a double-track bore between them.

 

Mostly arched apart from a short covered-way under the esplanade roundabout; that end also features quite a sharp reverse curve which also impacts gauging for long/wide/tall vehicles.

 

 

Yes, the 1983 proposal to introduce Class 503s to the Island (reproduced in my book 'Ryde Rail') recommended lowering the track through the twin-bore entrances and singling/realigning through the single bore central section.  No indication yet as to whether either of these options are considered necessary to fit the D Stock.

[Mike Storey]

I believe the D stock as per Vivarail, has two ride heights. The lower one would be used for the IOW, and is reflected in the alterations needed to platforms. Length is not a problem.

[PhilJ W]

33 minutes ago, Mike Storey said:

I believe the D stock as per Vivarail, has two ride heights. The lower one would be used for the IOW, and is reflected in the alterations needed to platforms. Length is not a problem.

That is because they used the same low profile bogies as the 1983 tube stock. Ironically the 1983 stock was once mooted as a replacement for the 1938 stock used on the Island Line but was rejected because of the single leaf doors of which it was said would cause problems for people laden with heavy luggage. This apparently is no longer deemed to be a problem as the D stock also has single leaf doors. The platform alterations will be neccessary because of the greater width of the D stock.  

[jim.snowdon]

8 hours ago, The Stationmaster said:

I see a comment has been made already but will the D78 stock really fit the tunnel at Ryde?  This has always been quoted as the reason why C1 restriction stock could not be used on the Island.  While the D78 dynamic envelope is probably not up to full C1 dimensions the vehicles are signficantly higher than tube stock.  Does their adoption mean the line through the tunnel might be singled to improve clearances I wonder?

The D78 profile is significantly smaller than the BR C1 gauge, both in terms of absolute height and the height/width at cant rail level, plus, the cars are quite a bit shorter, making for smaller end and centre throws.

 

Jim

[jim.snowdon]

4 minutes ago, PhilJ W said:

That is because they used the same low profile bogies as the 1983 tube stock. Ironically the 1983 stock was once mooted as a replacement for the 1938 stock used on the Island Line but was rejected because of the single leaf doors of which it was said would cause problems for people laden with heavy luggage. This apparently is no longer deemed to be a problem as the D stock also has single leaf doors. The platform alterations will be neccessary because of the greater width of the D stock.  

The 1983 stock used nominally the same bogie design as that originally fitted to the D78s (and originally trialled on a 1973 stock unit). The D78 bogies were subsequently replaced (almost certainly due to problems with cracking on LU's none too good track), so those under the units now with Vivarail are a newer design. As far as the car widths are concerned, whilst I don't have any dimensions to hand, I don't recall there being much, if any, difference in the car body widths - the only LU stock that was significantly wider (and route restricted) was the A60/62 stock.

 

The single leaf doors were something of an own goal on LU's part. The theory didn't really take into account the propensity for people to stand in the doorways and whilst, with hindsight, it was a poor decision to copy them on the 1983 stock, the probability is that because of the production lead times the design of the latter was committed before service experience with the D78 stock became available.

 

The 1983 stock was quite possibly also rejected for other reasons, one of which could have been the German designed electric camshaft equipment, which would have posed difficulties with spares and training compared to the 1938 stock's pneumatic camshaft controls, for which there was a considerable availability of spare parts.

 

Jim

[roythebus]

If I may refer my learned friends back to the aforementioned Brinton Report, i'm sure Mark Brinton's later report discussed the use of D stock on the Island. Track realignment would be required at the Esplanade end of the tunnel and in the tunnel, but it was reckoned top clearances would be ok if I remember correctly.

 

I can't see platforms being a problem width wise as they weren't altered when tube stock was introduced. There might be some track lowering through platforms to make wheelchair access easier. Track was raised in places to take this into account.

 

and in case anyone missed the earlier news, the IWSR has pulled out of discussions with the TOC regarding steam into Ryde. 

 

https://www.iwsteamrailway.co.uk/news/ryde-st-johns-road-latest-news-363.aspx

 

Edited September 18, 2019 by roythebus