Class 442 - Finally back in service on the LSWR.

[jim.snowdon]

5 minutes ago, phil-b259 said:

Traction return is a real pain for us signalling folk when it comes to track circuit faults.

It could be said that the E&P folk think the same when it comes to signalling, but when it comes to it we do all get along with each other reasonably well. We have to, or the job stops .

 

Traction return on a multiple track railway can be a real problem, in that with all the rails cross-bonded at intervals there are multiple parallel paths between the load and the substation(s) providing the power. There is a high level of redundancy in the whole set up, which is fine for minimising return impedance, but allows faults to be hidden. Not only that, but in taking different routes to get round a fault, current flows can potentially reverse locally, or simply become unbalanced, all things that are a pain to our signalling friends.

 

Jim

[phil-b259]

22 minutes ago, Nearholmer said:

Has the sensitivity of the track circuits to imbalance been deliberately increased, or allowed to increase, since this stock was last used in the area?

 

 Not to my knowledge.

 

The TI21 track circuit itself has been ‘digitised’ and now incorporates the ability to provide detailed + live data as to the state of key pentameter s via remote condition monitoring. The Sussex route had a upgrade programme a few years ago converting all analogue versions to digital on the BML and it’s quite possible the Wessex route did the same. 

 

https://docplayer.net/28867426-Ebi-track-200-ti21-audio-frequency-track-circuit.html

[njee20]

15 hours ago, St. Simon said:

I've seen comments on Facebook complaining it is either fancy new electric motors or fancy new signalling, it is neither, the signalling is the same as it was when they last ran on the route (although filament heads have been changed for LEDs, but that shouldn't be a factor) and they haven't had new traction motors fitted. 

 

It is simply the electrically 'leaky' 4-REP (I think) motors on the 442s are inducing a current in the Track Circuits on adjacent lines as they pass, causing the track circuit to drop. At least, that's how I understand it.

Surely these are at odds; it didn't happen for the 20 years they ran on the SWML, you're saying nothing's changed, yet now it's happening? It does sound like it's the "fancy new signalling" (insofar as the track circuits are part of that system, not just the twinkly lights people see)? Whether it's an actual equipment change (ie it's newer digital sensors which are triggered by the traction motors where analogue ones could filter out noise), or just that things are now closer to their maximum capacity due to increased load and are being tipped over the edge by the 442s as Phil suggests, it does suggest it's the signalling which has changed.

[DY444]

REP traction equipment messing up the signalling is not new.  When the REPs first started in the 60s there were certain signals that could be made to flicker through the aspects like Christmas tree lights by juggling the power controller in a particular way.  It became something of a (very unofficial) party trick amongst some of the drivers.  I'm fairly sure they got to the bottom of that though.  If the present problem is only happening in one place then that suggests to me there something amiss with the signalling installation at that location.

[The Stationmaster]

2 hours ago, phil-b259 said:

 

 Not to my knowledge.

 

The TI21 track circuit itself has been ‘digitised’ and now incorporates the ability to provide detailed + live data as to the state of key pentameter s via remote condition monitoring. The Sussex route had a upgrade programme a few years ago converting all analogue versions to digital on the BML and it’s quite possible the Wessex route did the same. 

 

https://docplayer.net/28867426-Ebi-track-200-ti21-audio-frequency-track-circuit.html

Ah, T121s - always a potential trouble spot with emissions from traction units.  They all had to be modified on Eurostar routes to deal with a potential interference issue but at least that also made them Class 92 proof.

[phil-b259]

6 hours ago, The Stationmaster said:

Ah, T121s - always a potential trouble spot with emissions from traction units.  They all had to be modified on Eurostar routes to deal with a potential interference issue but at least that also made them Class 92 proof.

 

I understood that it was the 'Reed' style of frequency track circuit which caused problems on routes used by Networkers, Eurostars and class 92s that were the problem (their existence north of Redhill is why class 92s are banned from the diversionary route via Redhill despite 3rd rail being present throughout). I believe many of the replacements were actually of the TI21 style.

 

There were also problems with that old Southern Region stalwart, the 50Hz AC track circuit and special relays are required to keep prevent issues happening.

 

 

[phil-b259]

8 hours ago, njee20 said:

 Whether it's an actual equipment change (ie it's newer digital sensors which are triggered by the traction motors where analogue ones could filter out noise),

 

The 'sensors'  (actually nothing of the kind - they are 'Trakside Tuning units' which attenuate all frequencies other than a specific one just like an analogue radio does) have not changed under the digital upgrade which is confined to the location case equipment.

 

Its still the case that ANY track circuit can be overwhelmed by traction interference if there is a weakness in the negative bonding or units have particularly 'leaky' traction equipment. As DY444 says the big difference these days is that signals briefly behaving like disco lights is less likely to be tolerated / be missed these days.

 

 

[Covkid]

the bit I am struggling to understand with the 442s is the suspension. I believe that when the 442s were transferred to the "Central Division" to operate the BML they received blocks in the suspension systems to raise the cars by either 7mm or 9mm (can't remember which). When withdrawn most were hauled off to Ely for storage but are now back being put through the works, however, due to the suspension mods I believe there are routes or tracks in the London area they are banned from.   

 

Now being an old fashioned kind of bloke I would just have removed those little blocks from the suspension and returned the 442s to their original ride height, but there has to be a reason why that hasn't been done. 

[Zomboid]

If they're still ok to run on the SWML with the modification in place, why spend the money to make an unnecessary change?

[njee20]

I’ve heard they’re banned from platforms 1 and 5 (IIRC) at Woking because of the increased ride height. Consequently they hold up everything on the fast lines as they can’t go through on the slow. 

[The Stationmaster]

On 03/09/2019 at 19:44, phil-b259 said:

 

I understood that it was the 'Reed' style of frequency track circuit which caused problems on routes used by Networkers, Eurostars and class 92s that were the problem (their existence north of Redhill is why class 92s are banned from the diversionary route via Redhill despite 3rd rail being present throughout). I believe many of the replacements were actually of the TI21 style.

 

There were also problems with that old Southern Region stalwart, the 50Hz AC track circuit and special relays are required to keep prevent issues happening.

 

 

There are other reasons as well for 92s being banned via Redhill (certain required signalling/locking upgrades never carried out because the existing processors were 'full' and nobody would pay for an additional unit).

[Covkid]

4 hours ago, Zomboid said:

If they're still ok to run on the SWML with the modification in place, why spend the money to make an unnecessary change?

 

Maybe on the SWML but the post below yours suggests problems at Woking, and I had heard problems at the London end.  I assume the bogies need their suspension overhauling periodically and maybe prior to a return to service in "refurbished" form.  

[phil-b259]

5 hours ago, The Stationmaster said:

There are other reasons as well for 92s being banned via Redhill (certain required signalling/locking upgrades never carried out because the existing processors were 'full' and nobody would pay for an additional unit).

 

The BML (until the last couple of years) had relay interlockings of various types at Redhill (including Westpac) and all points north. The only computer based ones are on Kent - and the route via Tonbridge was fine for Eurostar’s. As such while Interlocking modifications may have been needed, said changes would have not required software changes - rather good old fashioned rewiring.

[DY444]

On 05/09/2019 at 07:54, njee20 said:

I’ve heard they’re banned from platforms 1 and 5 (IIRC) at Woking because of the increased ride height. Consequently they hold up everything on the fast lines as they can’t go through on the slow. 

 

A few weeks ago certainly they were banned slow lines both ways from Basingstoke and from some platforms at Waterloo hence the reason for the 9XXX reporting numbers.  Also reported that they were being double manned because there were so many route restrictions it was a distraction and a second driver was needed to assist in ensuring a wrong route wasn't accepted or an RA speed restriction overlooked.  NR supposedly working on dealing with the infrastructure (starting with Waterloo as the platform restrictions were a big pain) so the situation may have changed since I last heard.

Edited September 9, 2019 by DY444

[adb968008]

On 09/09/2019 at 07:58, DY444 said:

 

A few weeks ago certainly they were banned slow lines both ways from Basingstoke and from some platforms at Waterloo hence the reason for the 9XXX reporting numbers.  Also reported that they were being double manned because there were so many route restrictions it was a distraction and a second driver was needed to assist in ensuring a wrong route wasn't accepted or an RA speed restriction overlooked.  NR supposedly working on dealing with the infrastructure (starting with Waterloo as the platform restrictions were a big pain) so the situation may have changed since I last heard.

Just checked my videos made this summer, and in each case there was two staff in the cab.

[Fat Controller]

On 05/09/2019 at 12:00, The Stationmaster said:

There are other reasons as well for 92s being banned via Redhill (certain required signalling/locking upgrades never carried out because the existing processors were 'full' and nobody would pay for an additional unit).

Were there not also power supplies between Redhill and Tonbridge, even though it was a new electrification? IIRC, there were also restrictions on 442s bound for Chart Leacon, so only one could traverse the line at a time.

[ess1uk]

If you had written a script for a film about this it would be unbelievable!

[Zomboid]

7 hours ago, Fat Controller said:

Were there not also power supplies between Redhill and Tonbridge, even though it was a new electrification? IIRC, there were also restrictions on 442s bound for Chart Leacon, so only one could traverse the line at a time.

Tonbridge to Redhill was built for 92s (at a relatively low frequency). Railfreight paid for it, because NSE claimed (laughably) that they would continue to use the diesel traction that they had at the time.

 

RF also built some new substations on the Redhill - London line, though not all were commissioned until the MK1 replacement project came along and needed them. In terms of enough electricity being available, Tonbridge to Redhill would be fine with a 92 or 373, though other factors mean that hasn't happened.

[Zomboid]

442s seem to be back in service with SWR again. Saw a 10 car set at Waterloo yesterday afternoon.

[298]

1 hour ago, Zomboid said:

442s seem to be back in service with SWR again. Saw a 10 car set at Waterloo yesterday afternoon.

 

4x pairs out, after modifications to their static converters.

[duncan_m]

It seems they’re still not ready. Was pleasantly surprised to see one coming in to Havant this morning but so far it’s been travelling very slow at points and is running about 20 minutes late. The Guard’s announcements say it’s down to to power supply problems and door problems.
 

Still seems weird to me that they’re having problems with these things.

 

 

[surfsup]

15 hours ago, duncan_m said:

It seems they’re still not ready. Was pleasantly surprised to see one coming in to Havant this morning but so far it’s been travelling very slow at points and is running about 20 minutes late. The Guard’s announcements say it’s down to to power supply problems and door problems.
 

Still seems weird to me that they’re having problems with these things.

 

 

 

From Railforums : There is a peak period power reduction in place between Liphook and Petersfield in both directions in addition to the power reduction at Haslemere to Witley on the up.

 

This is due to the 1930s equipment still in daily use on the Portsmouth Direct. 

[Zomboid]

Much of the original stuff has been renewed now, a more significant issue with the Portsmouth line is that there's nowhere that's strong enough and near to the railway to get a grid infeed between Portsmouth and Woking.

 

The power restriction would affect 442s more than desiros because of how the control system works on the trains. Camshaft controlled trains like 442s can't go beyond notch 2 which limits both the current and the speed they can attain, but with a variable frequency drive like a desiro the current limiter reduces the tractive effort available, but not the speed which they can ultimately achieve. At least that's what I was told years ago when 450s were brand new. (An analogy I recall is that a camshaft controlled train has full use of the accelerator, but only 1st and 2nd gears, and a frequency drive has the whole gearbox but only 25% of the accelerator travel)

Edited January 9, 2020 by Zomboid

[Enterprisingwestern]

 

Why don't they convert the Southern Region to DCC? As we modellers all know, it's only 2 wires and it doesn't give any problems!

 

Mike

[Southernman46]

On 03/09/2019 at 09:32, jim.snowdon said:

 I think one area I would start looking at is the negative bonding and where the return currents are going. A location specific fault like that hints at a trackside failure rather than rolling stock, although with a four track line, the multiple return paths offer all manner of possibilities for obscure failures.

 

Jim 

Absolutely …………. is / was always the case - NB is one of the most neglected areas of the DC traction network - an opinion born out of experience on the SR