PJM
Member
Absolutely, a quick drive through Great Bowden today confirms this.
-
Our new ticketing site is now live! Using either this or the original site (both 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!
MML Electrification: progress updates
- Thread starter LNW-GW Joint
- Start date
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R
RailUK Forums
59CosG95
Established Member
Updates on the MMLE Map:
Piling between East Langton & Newton Harcourt (22:00 - 06:00) - Fri 03/02/23 to Sat 18/02/23 & Fri 24/02/23 to Fri 03/03/23
Piling between Braybrooke & Great Bowden (22:00 Sat 18/02/23 to 06:00 Sun 19/02/23? - unclear)
Mast & Wire installation between Rushton & Braybrooke (23:30 Sat 25/02/23 to 07:30 Fri 03/03/23); this goes through the Desborough Gap
Vegetation Management between Great Bowden & South Wigston (07:00 Sat 04/02/23 to 17:00 Sun 12/03/23)
DEP Installation within Market Harborough Station (22:00 Sat 04/02/23 to 08:00 Fri 03/03/23)
Piling between East Langton & Newton Harcourt (22:00 - 06:00) - Fri 03/02/23 to Sat 18/02/23 & Fri 24/02/23 to Fri 03/03/23
Piling between Braybrooke & Great Bowden (22:00 Sat 18/02/23 to 06:00 Sun 19/02/23? - unclear)
Mast & Wire installation between Rushton & Braybrooke (23:30 Sat 25/02/23 to 07:30 Fri 03/03/23); this goes through the Desborough Gap
Vegetation Management between Great Bowden & South Wigston (07:00 Sat 04/02/23 to 17:00 Sun 12/03/23)
DEP Installation within Market Harborough Station (22:00 Sat 04/02/23 to 08:00 Fri 03/03/23)
PJM
Member
Shots taken from Langton Road, once again near the A6. Cantilevers have appeared! Driving south on the A6 I counted approximately 10 cantilevers and about 20 assorted masts ( very rough figures) . I will try and get better shots from the footbridge in the next few days.
Nottingham59
Established Member
I respectfully, disagree. TTC's need to be heavier to support the wider lever action, and the truss formation is far more intrusive than contemporary lines in Europe, e.g. the Betuweroute. I completely understand the economic rationale for single pilings, but lets not get away from the fact that STCs would be lighter on the eye.
I just get a green rectangle fpr the upper picture you've included, but the lower pictire of a STC looks like the 'low uplift' type of installation as is used on MML south. The reduced uplift performance caused by the smaller distance between the catenary and the contact wire has been suggested as the reason for upgrading the MML (S) as part of the preparations for the introduction of 125mph electric train operation. This is particularly so in the stretch from Hendon to Mill Hill which runs alongside the M1.
GRALISTAIR
Established Member
the sniper
Established Member
- Joined
- 4 Sep 2007
- Messages
- 3,498
Well, it's got that going for it!
59CosG95
Established Member
The STC in the picture is actually one of the "high uplift" ones seen on the ECML. I think NWR are having a serious look at this, but the scope still needs to be signed off.
Photos of the various equipment are found in this document: https://assets.publishing.service.g...ead-line-equipment-ole-support-structures.pdf. Part 2 of the report is the important bit for the images.
[link to UK Government report into use of OLE masts for radio antennae mounting, images included within]
I think what makes the GWML particularly egregious is the amount of steel protruding above the horizontal beams. Although it is also generally weightier, I don't think it's much worse in that regard than the 60s stuff out of Euston.
[link to UK Government report into use of OLE masts for radio antennae mounting, images included within]
I think what makes the GWML particularly egregious is the amount of steel protruding above the horizontal beams. Although it is also generally weightier, I don't think it's much worse in that regard than the 60s stuff out of Euston.
LNW-GW Joint
Veteran Member
Is it me, or was the original WCML wiring all "below the beams" (mostly 4-track portals)?
I'm sure extra cantilevers appeared above the portals during WCRM, perhaps to cope with the heavier/higher-tensioned catenary for 125/140mph.
My perception is that the WCML OHLE is more complicated than it used to be.
There's definitely new stuff in between the old portals where stations were rebuilt or speeds increased. I only started using the WCML in 2017 so haven't got a clue what it was like before WCRM.
Having said that, here in NL much of the catenary wire is suspended above the portal frame without it looking massively untidy. Of course here it's DC so simpler wiring, and 1.5KV so less clearance required, and speeds are generally lower so the forces involved in tensioning the wire are less.
See: https://www.greencarreports.com/new...s-now-running-on-100-percent-renewable-energy for a photo of some fairly typical Dutch structures.
Attachments
edwin_m
Veteran Member
Other things being equal, DC wiring is usually heavier than AC, as it has to carry higher currents.
That portal arrangement is typical of 1500V OLE, if the GE and Manchester Glossop lines were still DC, their catenary wires would still be strung over the frames.
59CosG95
Established Member
The main reason why the masts protruded so often above the booms on portals & TTCs (particularly with the "hook & pin" TTCs, but also the Monoboom Anchors) was for ATF supporting purposes. Vertical "gallows" ATF supports had the highest protrusion:
Rather strangely, this method of ATF support was chosen to reduce wind loading on the masts!
Much of the GWML had to be larger to take the wider spacing between tracks (a legacy of Brunel's Broad Gauge) into account as well, so that's why some of the masts are fairly beefy there.
Thanks for the explanations.
No, the catenary wire was often (but not always) above the booms Pre re wiring in the early 2000s.
The method of support did change though, hence the new cantilevers.
Nottingham59
Established Member
I understand the masts also had to be set significantly further away from the tracks than had been planned, because the piles kept cutting into buried signalling and communications cables which weren't where people expected them to be.
WesternBiker
Member
Is it not also the case that the GWML structures are designed to facilitate the higher tensioning to permit 140mph running?
PJM
Member
A couple of shots looking north from the footbridge just north of the A6 road bridge.
Looking south towards the A6 bridge. There are two or three masts south of that bridge-a bit tricky to see.
Looking south towards the A6 bridge. There are two or three masts south of that bridge-a bit tricky to see.
TheHSRailFan
Member
- Joined
- 16 Jun 2018
- Messages
- 285
Honestly great to see the speed at which the Market Harborough to Wigston section of the electrification is gone. It does mainly seem like it is of the sections where the lineside is mainly flat with no real obstacles which are been done quickly and efficiently.
59CosG95
Established Member
Lovely shots @PJM! The access to the footpath at bridge SPC3-28 should still be reachable off Langton Rd shortly before it crosses the A6, unless contractors have fenced it off now.
I also have it on good authority that, south of Bedford, all Booster Transformers have been removed (as far as Kentish Town SATS anyway).
Those bigger masts in the 1st & second picture look to me to be for a Mid-Point Anchor portal, judging by the extra trial holes south of the masts, and the height of the masts makes me think they'll anchor the ATF as well as the catenaries on the DM/UM. Perfect sense for the ATF to go into a trough there, as it has to pass under 3 overbridges and an overhead power line in fairly rapid succession.
I also have it on good authority that, south of Bedford, all Booster Transformers have been removed (as far as Kentish Town SATS anyway).
Those bigger masts in the 1st & second picture look to me to be for a Mid-Point Anchor portal, judging by the extra trial holes south of the masts, and the height of the masts makes me think they'll anchor the ATF as well as the catenaries on the DM/UM. Perfect sense for the ATF to go into a trough there, as it has to pass under 3 overbridges and an overhead power line in fairly rapid succession.
PJM
Member
On checking Google maps 59CosG95, you are absolutely correct about the footpath to bridge SPC3-28, I didn`t realise there was another bridge there! Will check it out next time.
SouthEastBuses
On Moderation
Is this between Market Harborough and Leicester? If that's the case, then it's good to see MML electrification progressing further than we originally thought it would have!
Also, on a more general note, let me guess, the Midland Mainline is also using the 2x25 kV system? (as found on the GWML, HS1, and high speed railway lines in France and Italy)
It is indeed.
SouthEastBuses
On Moderation
Fantastic! I wonder when will works start on the next section (north of Wigston)?
Nottingham59
Established Member
By 2x25kV, do you mean using ATF (autotransformer feed) which supplies power to the line through two cables at +25kV and -25kV? With intermediate transformers to transfer power from the separate ATF cable (at -25kV) onto the catenary wires (at +25kV)?
If so, then I understand only parts of the MML use this, but the rest is "ATF-ready" if needed to boost the power at a future date. This post (above) has more details:
[EDIT. By -25kV, I mean 25kV AC which is 180 degree out of phase with the catenary supply]
59CosG95
Established Member
Shortly after the contractors are announced, I'll wager.
Currently, RS1 (Mkt H'boro' to South Wigston) has been tacked on to KO1a of the original chopped programme (Kettering - Mkt H'boro') as it's a relatively easy win (two tracks, no additional grid connections, signalling already compliant etc.)
RS2 through RS8 are still out for competitive tender.