Efficient terminus station throats

[AndyLandy]

I've recently been pondering on how you would most efficiently design a station throat for a terminus station. My initial thoughts came from trying to build such a thing in OpenTTD, but it got me thinking to how it's done in the real world.

I know Euston has all those 'burrows' that grade-separate trains, but I've never really looked into how it works. On the other hand, somewhere like Waterloo isn't grade-separated at all. If anything, it can almost be viewed as three or four smaller terminals, all adjacent to one another, with the line sorting all happens at places like Wimbledon and Clapham Junction.

I guess the major contributing factor is what configuration of railway lines comes into the station (are the lines paired as up/down or as fast/slow, are there multiple different lines converging, that sort of thing). How's it done at other major terminus stations, and why?

Any input gratefully received.

 

[cle]

Many are fast/slow, or long distance/short distance - with the platform widths and facilities that correspond.

Waterloo is three stations - Windsor, Outer and Inner.
Victoria has four typical layouts - via Herne Hill, via Denmark Hill on the bidi, inner Clapham, outer Clapham - with the Gatwick Express in between but an outer service.

Many others are usually by service pattern, not up/down, all throats need to be bi-di to some degree.

 

[tsr]

Victoria has four typical layouts - via Herne Hill, via Denmark Hill on the bidi, inner Clapham, outer Clapham - with the Gatwick Express in between but an outer service.

Although of course what I shall refer to as Southern/GatEx platforms (for simplicity) are interchangeable, so it is easy enough for a Southern-branded train to use a Gatwick-Express-branded platform, and vice versa, where needed.

(To be pedantic! )

 

[snowball]

Approaching King's Cross the fast lines are at first in the middle, as they have been for many miles, but then a 1970s flyover carries the up slow over the fast lines so that the fast lines are then on the east and the slow on the west, which is better for turning trains round.

At Euston there is the strange phenomenon of the slows in the middle, with a few platforms in the middle being dual electrified for local trains. Historically long-distance arrivals were on the east side and departures on the west. The burrows were then used to take away empty coaches from one side and bring them back to the other, and to move locomotives around.

 

[PaulLothian]

I believe that the most intensive use of terminus platforms in the steam age, and possibly since, was the Great Eastern's Jazz service on its suburban lines, where a two-minute turn around was possible ( see http://www.lner.info/forums/viewtopic.php?f=5&t=941) I remember reading that two lines would serve up to six platforms, with arrivals and departures scheduled so that almost all were parallel movements, and with minimal crossing movements.

 

[JamesRowden]

There is London Charing Cross which has 28tph (28 arrivals) during the peak even though it has a double tracked approach (between London Bridge and Waterloo East) and only six platforms.

Heading towards Charing Cross, the double tracked line splits into two double tracked lines with all four lines having platforms at Waterloo East. Each of the double tracked lines then have three platforms at Charing Cross. By splitting the crossing movements to two seperate locations, it provides greater capacity than just having a double track leading straight into six terminus platforms at which all crossing movements would occur.

In games such as OpenTTD I have found that if one wants to get the greatest capacity from a terminus station with many trains coming from the same section of double track, it is good to split the line into multiple double track sections (with grade superation) and give each set of double track a certain number of platforms (e.g. two).

 

[edwin_m]

What all the above have in common is lines paired by use on the approach to the terminus, so that a train approaching the station throat on a particular line nearly always leaves on the adjacent line, thus minimising the amount of crossing from one line to another. As mentioned, termini where the lines further out are paired by direction ideally need a flyover to switch to paired by use on the approaches. Manchester Piccadilly has a flat crossing instead.

Euston is a bit unusual in that I think the eastern platforms were for arrivals and the western ones for departures, with local trains arriving and departing at shorter platforms in between. The various grade separations were originally intended to get the arrivals out to carriage sidings and later back in as departures, as well as bringing the slow and DC lines into the middle of the layout, but have now been reorganised to allow fast trains to arrive and depart on either side.

 

[Joseph_Locke]

To design a terminal station from scratch isn't a frequent task, to say the least. In an ideal world you'd match the number of platforms to the peak number of trains you need to accomodate: if you had two arrival roads and a typical 3 minute headway, that's 40 trains an hour; on a 30 minute turnround you need 20 platforms. The platform length will be determined by a) the longest trains and b) how much "platform sharing" (permissive working) you can stand; one 11-car Extendalino + Thunderbird will take 12 cars-worth of units, which in the impoverished north is a theoretical 12 trains...

However, designing to a timetable is a very bad idea indeed, so you would always try and include some "spare" and some passive provision for platform extensions.

The S&C in the throat also affects headway (each point end takes time to respond to a command, unlock, throw, re-lock and detect - M63s can take 30 seconds) so the more S&C you're moving for each platform the slower the process gets.

Grade separating arrival and departure lines is a noble thought, but you can't really do it at a multi-platform station. As previous posters have noted, segregating the station into groups of platforms by route (e.g. urban, suburban, regional, long distance) means the platform length and signalling can be optimised a bit, and you can always provide a grade-seperated inter-route junction a bit further out (like Euston has).

Also, you need to allow enough crossovers for when parts of the station or pairs of approach lines are closed for maintenance.

Lastly, the theoretical speed at the end of a terminal platform is 0mph 5m short of the buffers, which will affect your headways, the headways on the approaches and the choice of turnout speeds to avoid approach controls. At very low speeds the headway+overlap distance may be shorter than the longest train, creating a maximum tph for that layout.

So, apart from that, it's dead easy

 

[jopsuk]

For commuter services ideally you avoid city centre terminals. Much more efficient to have a through line that fans out to a series of quieter terminals in the sticks. Terminals should really only be for long distance services. In London, really only Weymouth, FGW High Speed, Chiltern Mainline*, Virgin, EMT, EC and Norwich services should terminate in the city.

Rebuilding the network to arrange for this would be horrific...

*maybe not even these. Perhaps only some extended Silver Services?

 

[Mojo]

The two platform terminus with a scissors crossover at Brixton Victoria line handles 33tph in the peaks

 

[edwin_m]

For commuter services ideally you avoid city centre terminals. Much more efficient to have a through line that fans out to a series of quieter terminals in the sticks. Terminals should really only be for long distance services. In London, really only Weymouth, FGW High Speed, Chiltern Mainline*, Virgin, EMT, EC and Norwich services should terminate in the city.

Rebuilding the network to arrange for this would be horrific...

*maybe not even these. Perhaps only some extended Silver Services?

You probably need some sort of turnback facility though, to handle the run up to and down from peak periods.

 

[Bevan Price]

The simplest way would be a terminal loop line, as for example the Liverpool loop on the Merseyrail Electric Wirral lines. A big problem is that unless it is underground, it occupies a lot of (expensive) land. Probably suitable only for local / commuter services and stock designed for rapid alighting / boarding. Would now cost far too much to establish loops in London or most other big cities, but might have been feasible if it had been done when they were building railways in the 19th century.

 

[HSTEd]

As I have learned by playing TTD/OpenTTD since its first release, the most efficient layout for a terminal station is a through station on a balloon loop.

All trains approaching from the same end of the station and departing from the same end.

 

[61653 HTAFC]

We're in danger of descending into a games discussion, but I used the reconfigured Bradford Interchange as a prototype on OTTD and found it fine for a level of service vaguely double the number of movements at the real thing. Certainly a good way of countering the awkwardness of the layout in both cases.

 

[RichmondCommu]

I think you would have to say that St Pancras is pretty efficient, in particular the four EMT platforms. All in all it's a good job because there isn't any scope for adding any more platforms!

 

[transmanche]

The two platform terminus with a scissors crossover at Brixton Victoria line handles 33tph in the peaks

I seem to recall that it was 'somewhat troublesome' before it was replaced (about a decade ago?).

 

[brianthegiant]

You could also convert the terminus into a through station for inter city services as per the very costly Stuttgart 21 project....

 

[jopsuk]

With Intercity services it only makes sense to do that if there's a logical destination beyond. Even just a depot makes sense- means that you can clean and prep the trains away from passengers, and depots can be in unfashionable areas out of town leaving the main station with a minimal footprint in the expensive areas.

Converting to through trains to avoid having ineffcient terminals is part of the point of Crossrail-type projects- 1 deals with the GWML and GE Metro services, 2 will likely deal with the SWML Metro in Waterloo and probably much of the Lea Valley Lines Metro.

 

[cle]

Loops never get suggested for relieving London termini as an alternative to the RER/Crossrail model, do they?

Where might this be viable in London, I wonder. And would it be worth adding a one platform/one directional station before it returns outbound?

 

[jopsuk]

Tunneling straight through and connecting to the other side (In London) provides relief for Underground lines groaning at the seams- eg Thameslink roughly parallels the Northern line, Crossrail 1 will take pressure off the Central, Crossrail 2 as proposed will help somewhat with the Victoria line

 

[edwin_m]

Tunneling straight through and connecting to the other side (In London) provides relief for Underground lines groaning at the seams- eg Thameslink roughly parallels the Northern line, Crossrail 1 will take pressure off the Central, Crossrail 2 as proposed will help somewhat with the Victoria line

It also avoids the bottleneck at the terminus where the number of people leaving the main line train and going into the Underground (and vice versa in the evenings) can be a limit on station capacity. A Crossrail-type service, or even HS2 at Old Oak Common, serves more destinations directly and also shares the load of changing passengers between several stations.

 

[eps200]

Loops never get suggested for relieving London termini as an alternative to the RER/Crossrail model, do they?

Where might this be viable in London, I wonder. And would it be worth adding a one platform/one directional station before it returns outbound?

That exists in liverpool and is invaluable, trains start and end the loop at james street.

The loop in liverpool makes sense because four stops can cover the city centre which is almost all journeys the rest are picked up by good interchange.

London isn't like that there are hundreds of places people might be going and no one place to catch everything. You would probably get a mess think the circle line but one way. Only other city I can see it working in is Leeds.

London is better served with more crossrails and thames links.