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Junctions on RETB

Discussion in 'Signalling M.I.C.' started by southyorkshireman, Jan 21, 2008.

  1. southyorkshireman

    southyorkshireman New Member

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    On stretches long stretches of line which are controlled by RETB, such as Scotland, how are diverging routes set and signalled?

    For example:

    Georgemass Junction (Wick to Thurso)
    Dingwall (Kyle line)
    Crianlarich (Oban)

    How do signalboxes within RETB sections (such as Fort William) know whether sections are clear to enter, do they have repeater token equipment?

    And how is the entry to an RETB line from a conventional line controlled?
     
  2. Ian Riley

    Ian Riley Member Loco Owner

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    Point 1; not sure!

    Point 2; the signaller is aware of whether a 'token' has already been issued for that section, or its availability for issue.

    Point 3; a driver may not enter an R.E.T.B. section unless he has already obtained, and the relevant section token is on his equipment display.
     
  3. m1ss_wh1te

    m1ss_wh1te New Member

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    Wouldn't the three lines approaching the junction be treated as three seperate single line sections?
     
  4. JAmieNWR

    JAmieNWR New Member

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    My understanding that all 3 routes will be 3 different sections to the signal(s) protecting the junction,
     
  5. southyorkshireman

    southyorkshireman New Member

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    But if its miles from the nearest box, and not TCB does it not require some kind of crew intervention to set routes?
     
  6. JAmieNWR

    JAmieNWR New Member

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    As far as I'm aware no (but I could be wrong), Mr Riley might be able to explain a bit better as he has worked on the Fort William - Mailaig route but my understanding is that when the train reaches the end/start of the tokenless block/RETB section, the driver radio's/calls the controlling box to tell the signaller that the train has reached the end of the block section, and if the section ahead is clear the signaller issue's the token to the drivers display to give the train the authority to enter the section ahead.

    This is my understanding as I have had no experiance in RETB sections so far.
     
  7. Small Prairie

    Small Prairie New Member

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    now im sure Riley will come online and go what the hell is he on about this time lol

    but i think your right ,

    ( i guess its easy to explain it as if your going into malliag .)

    but your outside mallaig with the ( i guess long section from glennfinnan ) showing on the screen as

    Glennfinnan - Mallaig
    Long Section

    then once your in the station at mallaig and clear of the points done your run round etc you can then phone up the signal box ( is it banavie box? ) tell the signaler that your out of section and that the section is clear then once his ready you "send" your token by radio to him and then it will be a blank screen , which will then alow the next train to take the token from where ever .

    then once your ready to leave mallaig , you phone banavie box and ask for the section to glennfinnan i guess . he will then tell you his ready to send his radio token to you and so the driver will press "recive" on the dysplay box , which acts like a normal token but just its electrical

    i hope it makes sence , and i hope ive not made a fool of myself trying to explain what is probuly wrong lol ( if it is then ready my signiture . im willing to learn lol)
     
  8. southyorkshireman

    southyorkshireman New Member

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    Mitch that is correct what you say, apart from I think run round using groundframes need a shunt token which releases the key in the front of the RETB unit.

    I'm asking about junctions rather than passing points on RETB lines.

    Ian I think has already added what he understands further up
     
  9. Small Prairie

    Small Prairie New Member

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    ahhh yes , sorry i forgot that bit ....hmmm , im interestted now lol
     
  10. Small Prairie

    Small Prairie New Member

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    not sure if this is right or not ,,,,,pure guess

    but this picture click to see

    almost looks like the point has a motor attached and can be set by a radio signal ?
     
  11. Guest

    Guest Guest

    I really don't know much about this but have observed RETB on the Cambrian. When a train is crossing at an ordinary loop are the points first set by treadles hit by the first approaching train? Are there stop boards on the outskirts of stations to prevent over-running of trains when crossing? It's been a while since I was in Tywyn and the memory is little vague!
     
  12. southyorkshireman

    southyorkshireman New Member

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    On a basic passing loop, they are sprung (hydraulicly I think) to the left and can be passed over in the trailing direction. On the approach a white light indicates they are set correctly to the left. The Stop board acts as the starter signal, and there is now a TPWS grid to prevent overunning, which is suppressed when the train has the token for the next section (whether this is radio controlled or the driver presses a button on the platform I am not sure

    The only junction on the Cambrian is Dovey, but that section is TCB between Dovey Junction and the east end of Mach station limits, as the box controlling the cambrian is located there.

    The Scottish junctions seem to be a long way from the controlling signalling centre
     
  13. Guest

    Guest Guest

    I wonder if the drivers simply radio in that they are clear of points and that they can be changed?

    I know that on the Far North the Control Centre does not always know what is going on...(a good friend used to work for BR/Railtrack/Network Rail and ran the Far North track maintenance programme for a few years and has some good stories about RETB).
     
  14. southyorkshireman

    southyorkshireman New Member

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    I've posted the question over on teh signalling section of Railchat, hopefully someone over there knows for definite
     
  15. burnettsj

    burnettsj New Member

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    From standing on Georgemas Jcn platform (though no train was there) I believe its a driver operated button on the platform.

    Crossing points on the cambrain do not require any off footplate work by the crew ( as witnessed on 7802's last trip).

    Stephen
     
  16. Sugar Palm 60526

    Sugar Palm 60526 New Member

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    As far as I know, for Fort William, it goes like this:-

    A train travelling from Glasgow is arriving at Fort William with the Spean Bridge- FW token on display (ie under the control of Banavie signal centre). It arrives at Fort William Junction and enters the control of the signalman at the junction for the route into the station. (The train will pass a fixed distant and then semaphore or colourlight home signals on the way in)(There are signals protecting the spur into the Alcan sidings).

    Even though the train has now come under the control of the junction signal box, the RETB token will not be surrendered until the train is stationary in the platform. Any shunting in the station or out to the yard or the MPD will be under the control of the FW Junction signalman without any need to contact Banavie Control Centre.

    If the train needs to depart for Mallaig, whilst still in the platform at Fort William, the driver will ask Banavie control centre for and be given the RETB token for Glenfinnan (It used always to be Loch Eil Outward Bound when the paper mill was open).

    The signalman at the junction will give him the colour light starting signal, the semaphore signal at the junction and the semaphore signal to enter the section (adjacent to the MPD). The train then enters the RETB section and comes under the control of Banavie. The driver will radio Banavie to say that he has entered the section.

    A goods train arriving from Glasgow would stop clear of the junction but would not go into the station. It would surrender the token and propel into the yard. Similarly the goods departing for Glasgow would propel out of the yard far enough to clear the yard exit and would depart, probably having obtained the RETB token in the yard.

    The only thing I don't know is how the FW Junction signalman and Banavie signallers communicate with each other but the obviously do. I'll try and remember to find out this summer!

    The junction at Crianlarich is completely under the control of Banavie. Any shunting moves there require a shunt token to be taken out as is the case at Mallaig. The sort of shunts we get involved in at Crianlarich are usually to get out of the way of a service train and involve running out of (say) the up platform into the down then back into the up once the sprinter has departed. All done by using the automatic spring points or the push button, driver operated, points at the junction for the Fort William or Oban lines.
     
  17. Sugar Palm 60526

    Sugar Palm 60526 New Member

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    I have just been given some more information, about the arrangements at Fort William Junction, by one of the regular Jacobite train crew. (Thanks). (It just shows who reads this stuff!)

    At FW junc and Corpach (a manned level crossing) the signallers have a Brunell radio this enables then to listen in on the RETB so they know when a train is approaching or ready to depart FW.

    The section signals at FW Junc, for trains departing FW for either Mallaig or Glasgow, are released by the issue of the appropriate RETB token thus ensuring a train cannot enter section without one.

    If trains are to pass on the Mallaig line in the loop at FW Junc both trains proceed to the junction stop and exchange tokens via Banavie signal centre.

    Under normal circumstances, on entering a section, the driver will transmit 'loop clear' so that the Banavie signaller knows that the section in rear and the overlap is clear e.g. at Glenfinnan. Leaving Fort William Junction this does not really apply, however it is still done for 2 reasons. Banavie know that the train is now in section, and going towards Banavie and they use this as a signal to lower the level crossing gates.

    The decision as to whether the train gets a short or long section token depends on if there are any engineers out. If the engineers are working between Loch Eil OB and Glenfinnan they get an engineers RETB short section token on the set in their van. So if the engineers have this token the train leaving FW will get the Short section token from FW to Loch Eil OB thus enabeling the engineers to work for the maximum length of time.

    Hope this helps.
     
  18. hussra

    hussra New Member

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    Crianlarich has a small amount of track circuiting at the north end and is essentially first come, first served for up trains (converging movements). Down trains press the appropriate plunger from the four at the end of the platform (two platforms x two destinations = 4 plungers) to select the desired route. This then motors the points across and the appropriate "points set" indicator lights up together with a theatre indicator. Photo here.

    The setup here was covered a number of years ago in The Signalling Record.

    Best wishes,

    Richard
     
  19. Marquis DeCarabas

    Marquis DeCarabas New Member

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    FCFS does not apply with RETB, there is a world of difference between RETB and PM [1] FCFS, though the devil might be in the detail of the circuitry or labelling the terminology we're familar with..... ITYM 'FCFC' (First Come First Called)
    :smt059 any comparison with a duplex Plaistow deserves to be dipped in fifth wheel grease.

    [1] err...... 'Programme Machine'

    Ooo. Hello and big wet kiss of welcome BTW - how's the fragrant self? ;-) [2]

    [2] wife, rather than you.
     

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