Modern UK Signalling - What do you want to know?

[St. Simon]

1 hour ago, Michael Hodgson said:

I wasn't aware that Lime Street Control had fallen out of favour. 

In principle it ought to be calculate the same thing by keeping track of train consists, but I suppose it would be necessary to integrate a lot of systems that don't currently talk to one another. 

Hi,

Maybe ‘falling out of favour’ is possibly the wrong term, but I’ve come across a lot of mumbling and requests to remove the controls.

 

I think they are a good control, the main problem is that they cant easily be changed to allow changes on train lengths and standback policies, so they can quickly become out of step with the operational requirements. However, if you use a clamped type Axle Counter (I.e Frauscher or Thales K series), it isn’t a massive issue.

 

Simon

[TheSignalEngineer]

2 hours ago, St. Simon said:

For info, Lime Street controls are increasingly falling out of favour and being removed from places as they are more trouble than they are worth.

Lime Street controls were really designed for the days of loco hauled trains. The primary purpose was to ensure that you had room to get a loco or two on the back end of a train to take it out of the station. 

We didn't have them at New Street which was designed primarily as a through station for loco hauled trains with mainly DMUs/EMUs changing direction.  

It wasn't such a problem there when trains started to reverse as long trains often used No.5 which was also had train watering facilities, very necessary with journeys as long as Penzance - Aberdeen. Terminating trains from the London end either used No.1 or No.4, both of which could take 16 coach trains. The other alternative used at busy times was for a terminator to continue out of the station to Duddeston (possible from either end of the station) to run round and return. Up ECS trains were looped in the Through Siding at Monument Lane to await their booked platform slot.

[The Stationmaster]

16 hours ago, St. Simon said:

Hi,

Maybe ‘falling out of favour’ is possibly the wrong term, but I’ve come across a lot of mumbling and requests to remove the controls.

 

I think they are a good control, the main problem is that they cant easily be changed to allow changes on train lengths and standback policies, so they can quickly become out of step with the operational requirements. However, if you use a clamped type Axle Counter (I.e Frauscher or Thales K series), it isn’t a massive issue.

 

Simon

Yes - they are very dependent on train formation and the plan of what you are intending.  I sent Railtrack (yes, it's real history) a very detailed spec for the installation of Lime Street Control at Waterloo International to enable safe working and shunting of the portions for ENS sleeper trans when I considerably altered completely redesigned the trainplan in order to massively reduce operating costs by totally taking out shunting of sections at Kensington and providng extra commercial opportunities.

 

Thus the control was specified around the lengths of the different sized portions of ENS stock and the various type of traction involved - Class 92, a pair of Class 37s with a generator coach between them, and a Class 73 (involved for what I called SETHS purposes.  (SETHS = Supplementary EGH Source, which I had to add to some formations in order to handle the hotel electrical load on 3rd rail).  Change the traction, change the stock, and the original specification parameters would change.    BTW the work was never done - fortunately

 

Just like introducing 4 and 5 car formations at Paddington instead of only 3 car/multiples of them being involved in attaching and detaching of sections.

[phil-b259]

On 20/12/2022 at 21:04, 5BarVT said:

 

Ah, but, ah, but . . .

The relays used to control a three aspect signal are still abbreviations of Home Relay and Distant Relay.

 

Always intrigues/amuses me when history can be seen in modern thinking.

 

Paul.

NO THEY ARE NOT! - the letters used in railway abbreviations do NOT relate to to what you might think they do!

 

The letters ‘HR’ in railway nomenclature refer to the words ‘Yellow Relay’ and a ‘Yellow Signal Lamp’ is a ‘HGE’

 

The letters ‘DR’ in railway nomenclature refer to ‘Green Relay’ and a ‘DGE’ is a Green Signal Lamp

 

(And a ‘points relay’ is a ‘WR’, a ‘Points Indication Relay’ is a ‘WKR’, the piece of equipment that energises an AWS magnet is a ‘GDIJ - a ‘Green Signal Inductor Rectifier to give some more examples)’

 

The relays which control a couloir light aspect are:-

 

‘HR’ / ‘Yellow Relay’  (if de-energised then the red aspect will be lit so it fails safe) which will light the single yellow lamp

 

‘DR’ / ‘Green Relay’

 

’HHR’ / ‘Yellow Yellow Relay’ (Double Yellow aspect.

 

To get a single yellow aspect only the HR needs to be energised

 

To get a double yellow aspect BOTH the HR AND the HHR relay need to be energised

 

To get a green aspect the HR AND the HHR (where fitted) AND the DR need to be energised.

[Grovenor]

3 hours ago, phil-b259 said:

NO THEY ARE NOT! - the letters used in railway abbreviations do NOT relate to to what you might think they do!

 

The letters ‘HR’ in railway nomenclature refer to the words ‘Yellow Relay’ and a ‘Yellow Signal Lamp’ is a ‘HGE’

 

The letters ‘DR’ in railway nomenclature refer to ‘Green Relay’ and a ‘DGE’ is a Green Signal Lamp

 

 

You are both right here, nowadays H means yellow and D means green but the origin of the H and D is Home and Distant. Both current practice and historical origins are correct, depending on context.

[St. Simon]

5 hours ago, phil-b259 said:

NO THEY ARE NOT! - the letters used in railway abbreviations do NOT relate to to what you might think they do!

Hi Phil,

 

Paul meant that ‘H’ and ‘D’ have their history in ‘Home’ and ‘Distant’ rather than that is their current literal meaning.

 

I can assure you that Paul really knows what he is talking about when it comes to signalling  and I have absolutely no doubt about his knowledge on these matters.

 

Simon

[St. Simon]

5 hours ago, phil-b259 said:

 

 

The relays which control a couloir light aspect are:-

Hi,

 

Just to add, this SW67 style interlocking, a Western E10K might be slightly different in the combinations of relay needed to get an aspect (although HR, HHR and DR are still used).

 

Of course, it is technically the ‘GR’ (‘Signal Relay’) that controls whether a signal can show an aspect better than a red in a SW67 RRI, whereas in E10K (if I’ve understood it right, I haven’t been fully trained on it), it is the ‘HR’ that does this.

 

Simon 

[The Stationmaster]

16 hours ago, St. Simon said:

Hi,

 

Just to add, this SW67 style interlocking, a Western E10K might be slightly different in the combinations of relay needed to get an aspect (although HR, HHR and DR are still used).

 

Of course, it is technically the ‘GR’ (‘Signal Relay’) that controls whether a signal can show an aspect better than a red in a SW67 RRI, whereas in E10K (if I’ve understood it right, I haven’t been fully trained on it), it is the ‘HR’ that does this.

 

Simon 

Paul will probably know better than me but hoing on what I observed in a location cupboard many years ago I think you will find that E10K is slightly different although the result is obviously the same.  I watched what was happening in a cupboard where the doors had been left open then went home and effectively replicated what I'd seen (using PO type relays) for my then layout (well it was c.60 years ago but the circuits worked perfectly giving exactly correct aspect sequences even when any signal in advance was returned to danger).

 

Since the move have you still got the E10K drawings in the office?

[St. Simon]

8 hours ago, The Stationmaster said:

Since the move have you still got the E10K drawings in the office?

Hi Mike,

 

Yes, we do, still on our shelf and used as reference!

 

Simon

[ewsclass66]

Where can relays still be found operating in SSI installations? Saw some LOCs propped open on a SSI scheme and saw relays installed so wondered what their function might be? cheers

[5BarVT]

You get relays at the boundaries of one scheme and the adjacent.  Point motors always required relays.  I think that nowadays point detection comes back on relays for each separate item e.g. front end and each supplementary detector, then combined in loc for input to SSI.  Reason for that is that it saves loads of time testing after an item has been changed.

Paul.

 

[St. Simon]

On 31/01/2023 at 21:37, ewsclass66 said:

Where can relays still be found operating in SSI installations? Saw some LOCs propped open on a SSI scheme and saw relays installed so wondered what their function might be? cheers

Hi,

 

I believe you can also find relays in SSI areas where there was once an RRI, but the outside equipment hasn’t changed. Some older Track Circuit and Point Mechanism types due too much current for SSI TFMs or can damage them, so use relays as an interface.

 

Simon

[43110andyb]

A track circuit input to the SSI module generally uses a front contact of the TR (track relay) so that there is no direct physical connection between the operating track circuit and the SSI input so many SSI cabinets will feature these relays.
   Points are a mixed bag! Low voltage detection clamp lock points don’t need any relays for detection input to SSI or output to pump units etc, over the years many have been converted to 50v detection circuits and relays fitted into cabinets that previously when introduced in the early 1990’s didn’t have any!  (Tyneside IECC).

    The interface between Tyneside SSI and York SSI at Wiske Moor near Northallerton uses relays (lots of them) for the cross over between the two!