I presume that's because the SFC uses all three phases, rather than because of any frequency conversion? In other words it's a more effective voltage converter than a regular transformer.
-
Our booking engine at tickets.railforums.co.uk (powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!
Decarbonising Scotland’s Railways
- Thread starter clc
- Start date
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R
RailUK Forums
HSTEd
Veteran Member
- Joined
- 14 Jul 2011
- Messages
- 16,739
Yes, SFCs are fully controllable converters so can draw loads from phases as demanded by the grid system (normally balanced but they could be commanded to draw an unblanaced load to correct overall grid inbalance).
paul1609
Established Member
What are the energy efficiency of these SFCs like compared to a straight transformer?
Nottingham59
Established Member
I understand they're called Frequency Converters because in Germany the railways used 16.7Hz AC at 15kV. When fed from 50Hz grid supply, i believe they used motor-generator sets with gears or rotor windings configured to covert the frequency to 16.7Hz. The latest sort presumably use electronics instead rotating machinery, hence "Static".
EDIT: Mostly right. See here for more info https://en.m.wikipedia.org/wiki/15_kV_AC_railway_electrification
Nottingham59
Established Member
Sounds right. Like a back-to-back HVDC.
Ignore, I mis-read your post.
and when it gets onto the train it is 50Hz single phase to DC to 3 phase variable frequency. Every conversion stage involves losses and inefficiencies. Overall though, it is still the most efficient process. Compare it to DC traction motors or diesel engines as part of a genset or with a mechanical gearbox or hydraulic transmission.
Elecman
Established Member
[QUOTE="snowball, post: 5761623, member: 19554"
When the south WCML was first electrified in the 1960s, how extensive was the 275/400kV network? Did many of the feeds have to be 132kV?
[/QUOTE]
No 275/400kV they were all 132kV.
When the south WCML was first electrified in the 1960s, how extensive was the 275/400kV network? Did many of the feeds have to be 132kV?
[/QUOTE]
No 275/400kV they were all 132kV.
Nicholas Lewis
Established Member
Not as good as a transformer but better than a rotary converter which was a common approach in Europe if the railway administration didn't generate at the desired frequency.
NR have this video doesn't give much on technical but you get a feel for the difference of a SFC installation compared to a normal NG site.
For some reason a tweet appeared yesterday about the Ferguslie feeder station that was delivered and placed circa July 11th and discussed above. Underneath somebody asks whether it's an SFC, and the reply is no.
There may be others here who, like me, do not usually spend much time in the rolling stock forum, so I think it right to draw attention to this new thread on the new trains needed for the decarbonisation programme. Scotrail Trains is seeking tenders for legal services in connection with the procurement.
-------------------------------- (automerged post 14 Aug) --------------------------------
I've been hoping for a while that one of the magazines would soon run a major feature on Scottish electrification. There's an article in the current RAIL (#963) that looked promising at first sight (8 pages including photos) but it turns out to answer few of my many outstanding questions on the current plan, and is largely historical, including a long list of dates of pre-2020 electrifications.
However I see that a photo caption on page 41 includes the precise endpoints and dates of the proposed Fife partial electrification.
South end: Kinghorn, 23 miles 1600 yards
North end: Ladybank, 40 miles 539 yards
Between these points to be wired by December 2024
West end: a point between Lochgelly and Cardenden, 29 miles 519 yards. Thornton to here to be done by December 2025.
As announced in the press release, Haymarket to Dalmeny is to be done by December 2024. A figure of 9 miles 1000 yards is mentioned, I think this is the location of the end of the wires at Dalmeny.
ScotRail’s New Trains Procurement Programme
An advert for a tender for legal services for the above (https://www.publiccontractsscotland.gov.uk/search/show/search_view.aspx?ID=AUG455691) gives some more detail on the fleet plan ScotRail Trains (SRT) plans to replace 65% of its train fleet (around 675 carriages) in the period 2027 to...
www.railforums.co.uk
-------------------------------- (automerged post 14 Aug) --------------------------------
I've been hoping for a while that one of the magazines would soon run a major feature on Scottish electrification. There's an article in the current RAIL (#963) that looked promising at first sight (8 pages including photos) but it turns out to answer few of my many outstanding questions on the current plan, and is largely historical, including a long list of dates of pre-2020 electrifications.
However I see that a photo caption on page 41 includes the precise endpoints and dates of the proposed Fife partial electrification.
South end: Kinghorn, 23 miles 1600 yards
North end: Ladybank, 40 miles 539 yards
Between these points to be wired by December 2024
West end: a point between Lochgelly and Cardenden, 29 miles 519 yards. Thornton to here to be done by December 2025.
As announced in the press release, Haymarket to Dalmeny is to be done by December 2024. A figure of 9 miles 1000 yards is mentioned, I think this is the location of the end of the wires at Dalmeny.
Last edited:
So that gives them three years to figure out what the plan is for Kinghorn tunnel and the Forth Bridge if they don't want a gap in the Edinburgh-Aberdeen electrification programme. Though, I guess that with relatively new BEMUs they can work on Ladybank to St. Fort or Dundee to Lunan.
The plan is, surely, the continued use of battery trains. A 15 mile gap is neither here nor there in battery terms.
Nicholas Lewis
Established Member
Indeed might as well accept now Forth bridge never going to be wired so why waste time and money trying to convince the heritage lot and just spend it on getting BEMUS in service.
There is no plausible reason to imagine that the Forth Bridge will not be wired in due course. On 7 September 2020, Alex Hynes, head of Scotrail, tweeted "Yes" in reply to the question "Can the Forth Bridge take electrification apparatus?". All indications are that BEMUs are proposed in Scotland only as an intermediate step to continuous electrification. There is no reason to believe that "the heritage lot" are presenting undue difficulty. They do not appear to be opposing the visitor walkway, for example.
My belief, however, is that the bridge and the south Fife tunnels will remain unwired for more than a few years. It's much better to continue partial electrification of further lines ("the easy bits") before returning to infill lines already partially electrified ("the hard bits").
Last edited:
“Can…” is a different question to “Will…”
One point perhaps worth mentioning is that with conventional electrification a major part of the capital cost is getting power supplies to the railway. When a line is partially electrified and operated by battery trains, this aspect is initially even more acute: you need to spend as much upfront on feeder stations as if you had been electrifying throughout. A train spends less time under the wires but draws more current while under them. But once you've reached the point where the line is sufficiently wired that it can be operated with battery trains, then (assuming unchanged traffic levels) no further expenditure is required on feeder stations when you infill the gaps in the wires.
Each time the batteries come up for replacement you have a new motivation to look at the costs and benefits of completing the infill.
Each time the batteries come up for replacement you have a new motivation to look at the costs and benefits of completing the infill.
I think that the gaps are quite likely to be filled on routes where there's heavy traffic to be honest. It's just that they probably won't receive attention until 2035.
There are more pressing issues. Battery trains for example aren't going to be capable of making it from Ayr to Stranraer and back because of the gradients. Hydrogen was the proposed solution but that is going to be such an astonishingly expensive way to operate a train.
I can't see that being the plan indefinitely.
Bald Rick may wish to see the map on show at around 29 minutes into the video linked in the first post of this thread and reproduced in post #8 of the thread, and the ensuing discussion of the meaning of the pink and blue sections on the map.
Admittedly they may have scaled back their ambitions in the last year.
Admittedly they may have scaled back their ambitions in the last year.
MadMac
Member
Could they manage Girvan-Stranraer? 50 mile return trip.
That's where the steep gradients are so hypothetically maybe it could be done, but not easily. And in any case there's not enough time to extend electrification from Ayr to Girvan in addition to all of the other works, so a transition solution is necessary.
Trainbike46
Established Member
would a charging solution at Stranraer be an option?
It could be, but in the current timetable the turnaround time is between 10 to 20 minutes - I'm not sure how much of a useful charge they could get in that time.
Yes, it's definitely a possibility, but of course that would require an additional diagram in order to extend turnaround time, so you'd be paying for an extra unit for the same frequency of service. Plus of course the cost of getting a compatible power supply into the station which is going to be expensive.
Before the pandemic the 0900 and 1903 from Kilmarnock ran through to Stranraer, and the 1230 from Ayr started back at Stranraer. There was also a 1303 and 2307 Kilmarnock to Stranraer, plus 1500 and 2103 Stranraer to Kilmarnock which no longer run. I do not remember if Transport Scotland would like these reinstated but it doesn't seem likely.
Last edited:
Since Scotland doesn't seem to be going in for stationary chargers, a more Scotland-like solution might be 12stk of wiring from Stranraer to the point where the line turns north 2km west of Glenluce, a feeder station there, and a 2km westward extension of the 132kV grid line that ends at Glenluce. (Wooden poles like the last miles to Marshall Meadows?)
However that's quite a big scheme, I suspect bigger than what they seem to be proposing at the south end of the Borders line. Also there probably isn't time to design and build it. Also I have no idea whether the spare capacity exists in the 132kV line.
Last edited:
Unfortunately I think that there is no hope for such a scheme for a route with 5 trains per day.
Yes. There isn't an issue in reality.
It isn't a problem in reality and secondly Scotland have relaxed from the 2035 target to 2040 so Ayr - Girvan can be done fairly late so there is no need for a transition solution.
I'm not much surprised or much disappointed to read that. I still expect them to be miles ahead of England.
Is there a published document stating the relaxation or giving a precise defintion of what the new target includes?