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Operation of miniature Webb and Thompson. ETS machines

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Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Thu Jan 21, 2016 2:25 am

Since its 30 years since I saw one of these being operated I'm now fuzzy on the exact sequence

The versions used in Ireland seemed to just have a single bell style plunger and were typically magneto powered . I've looked at old descriptive text books. But they refer to electrical diagram that suggest more switches then shown on the face of the instrument

My memory is the galvanometer had no markings

The older diagram suggest there was a switch to change the plunger from bell use to release magnet use and the diagrams refer to both local and line batteries. But this must be different with magneto operation

Can someone explain the step by step operation of these instruments. ?

Thanks

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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby Andrew Waugh » Thu Jan 21, 2016 5:03 am

It varied a little depending on the exact instruments.

Magneto instruments didn't have a bell plunger on the instrument itself; this was on the magneto box. A simple ES instrument had a central galvo with no markings, and a single switch (the cutoff) on the top left.

To send a bell signal you didn't touch the instrument itself. You swung the handle of the magneto and pressed the appropriate bell key at the front (Magies had two keys, one for each section.)

Usual bell code, send call attention, wait for the acknowledgement, send is line clear. The other end would acknowledge the is line clear, and on the last beat would hold the bell key while continuing to crank. You would lift a staff into the throat of the instrument. This lifted a crank inside the machine that operated a contact directing the incoming current away from the bell to the lock. As you continued to lift the staff, this lifted a second crank that lifted the electric lock and, if the polarity was correct, the mechanical lock that secured the drums. The staff could then be pulled through the circular path which rotated the drums a quarter turn and reversed the commutator. All this time the signaller at the other end would be holding the bell key down while cranking like mad. At your end you turned the cutoff switch at the top left of the instrument and held it hard over against a spring. This opened the line wire, causing the galvos on both instruments to assume the vertical position. This indicated to the signaller at the other end you had the staff and they could stop cranking (phew). The cutoff switch could then be released from the spring, but it would be left turned a quarter turn (indicating 'staff out'), but this was simply a reminder and had no mechanical or electrical significance. The other end was supposed to turn their cutout switch to show that a staff was out. Train departure would then be sent and received.

When the train arrived at the other end the operation was simplicity itself. The staff was put in the instrument (reversing the commutator at that end), and then train arrival was sent and acknowledged. The cutout switches would then be turned vertical to indicate that the section was clear.

More complex galvos existed (and I think were used in Ireland) that had subsidiary indicators marking if the section was clear, or if an up or down train was in the section. In Ireland, there was also the section signal release key. This was mechanically released by removing the staff, and, once released could be used to free the starting signal.

This process could be simplified. With an automatic operator at the far end, the process was to give a long beat on the bell. When this was released, the automatic operator would start feed current down the line. When the staff was removed, the cutoff would be held over to stop the automatic operator. At the other end of the section the staff would simply be sunk.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby Pete2320 » Thu Jan 21, 2016 11:23 am

I think references to the Bell/Staff switch refer to the earlier versions of the large staff instruments. Equally the reference to local batteries was for earlier instruments and polarised the line relay or lock, depending on type. The 1912 brochure for the 'S' type instruments comments that they are powered exclusiveley by the line current and that no local supply is neccessary. Certainly later 'M' type instruments used this arrangement and I think later 'Large' type. Essentially the polarising coil was replaced by a permanent magnet.
Where provided, the Bell/Staff switch was left in the 'bell' position which allowed bell signals to be exchanged. When a staff was to be withdrawn the man withdrawing the staff would turn his switch to 'staff' whilst the release was sent from the other end (however generated!) and turn it back to bell when the staff was out. (I presume it wasn't spring loaded to 'bell', it would be awkward to get a staff out perhaps needing three hands!) Some Tablet machines (eg Nos 5 and 7) used a similar arrangement.

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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby AndyB » Thu Jan 21, 2016 3:25 pm

There is a picture of the instruments at Mullingar here.

Most ETS sections here used Magnetos - Drogheda (for Platin)-Navan was one of the exceptions, and was operated by batteries - it's now operated by TCB.

Navan-Tara Mines is operated by conventional instruments, but still using a magneto - there is no starting signal release, because it is operated as a siding, and the main signals are fixed at danger, access across Navan level crossing being controlled by a disc. However, they are rarely if ever used - the main pair is for Navan and Tara and has a single staff in it (a second staff being padlocked to the mantlepiece for use as a manual staff), but the subsidiary instrument for Tara Junction still exists and lies empty. When the Kingscourt branch was still open, a Kingscourt train would take both staffs, use them both to unlock the ground frame at the junction, and put the subsidiary instruments back in phase with the S type so that trains could work to Tara while the branch was in use. The Tara instrument is unused except when a second train needs to approach while the first is at the mines.

I think the reason why there was no direct electrical signal release may have been because the block line belongs to Telecom Eireann, rather than Irish Rail.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby JRB » Thu Jan 21, 2016 3:59 pm

Privatised as "eircom" since 1999.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Thu Jan 21, 2016 5:25 pm

Andrew thank you for your excellant description

Usual bell code, send call attention, wait for the acknowledgement, send is line clear. The other end would acknowledge the is line clear, and on the last beat would hold the bell key while continuing to crank. You would lift a staff into the throat of the instrument. This lifted a crank inside the machine that operated a contact directing the incoming current away from the bell to the lock. As you continued to lift the staff, this lifted a second crank that lifted the electric lock and, if the polarity was correct, the mechanical lock that secured the drums. The staff could then be pulled through the circular path which rotated the drums a quarter turn and reversed the commutator. All this time the signaller at the other end would be holding the bell key down while cranking like mad. At your end you turned the cutoff switch at the top left of the instrument and held it hard over against a spring. This opened the line wire, causing the galvos on both instruments to assume the vertical position. This indicated to the signaller at the other end you had the staff and they could stop cranking (phew). The cutoff switch could then be released from the spring, but it would be left turned a quarter turn (indicating 'staff out'), but this was simply a reminder and had no mechanical or electrical significance. The other end was supposed to turn their cutout switch to show that a staff was out. Train departure would then be sent and received.


does that mean that initially the signaller , looking to release the staff, operated his magneto , merely to ring the remote bell, then the remote signaller , also operated his magneto to provide answering bells , then held his key down and continuing to operate his magneto, until he saw his galvanometer swing vertical ?

More complex galvos existed (and I think were used in Ireland) that had subsidiary indicators marking if the section was clear, or if an up or down train was in the section. In Ireland, there was also the section signal release key. This was mechanically released by removing the staff, and, once released could be used to free the starting signal.

yes Im aware of the signal release, thats straight forward , I cant think of any w& T machines in ireland that had writing on the face of the galvo. There were other galvo type system in use though ( like the famous zenograph )

thanks

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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Thu Jan 21, 2016 5:29 pm

I think the reason why there was no direct electrical signal release may have been because the block line belongs to Telecom Eireann, rather than Irish Rail.


The irish post office, which maintained the inter block telegraph lines, did so in effect under contract from the railways. I know this , because my grandfather for a time was an engineer employed by the post office to maintain such lines. If the railway company wanted more or less lines they simply asked for them. This was in effect a quid pro quo for allowing the post office access to the permanent way to run phone and telegraph lines ( which gradually migrated to road line lines in due course)

I believe this was the same system in the UK in general, as the post office was a unified operation during railway signalling installations at the turn of the 20 th century

irish Rail , re-establised control over the ETS line, when the track side posts were abandoned by the phone companies , and in general then ploughed the ETS line underground. ( rather then maintain posts ) However many line side posts continued to be used to this day , carrying both fibre and multicore phone lines . including echo cancellers on the posts etc


Some W&T machines were fitted with signal release keys and some were not, I suspect this was a simple method of adding interlocking to the W&T machine , where no permanent electrical supply was present , i.e. magneto operated.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby JRB » Thu Jan 21, 2016 8:20 pm

The GPO and successors had for many years a legal monopoly of telegraphs, so having the railway ones was not a voluntary decision. Policy & timing diverged with Irish independence.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Thu Jan 21, 2016 11:43 pm

JRB wrote:The GPO and successors had for many years a legal monopoly of telegraphs, so having the railway ones was not a voluntary decision. Policy & timing diverged with Irish independence.


As I understand it

until the Telegraph Act 1868, railways installed telegraphs of various types as private operators or contracted out such operations to private networks, many of whom used the railways permanent way to establish such systems often on a quid pro quo basis. ( hence carrying the railways traffic for free )

The Telegraph act , actually firstly placed all such telegraphic systems that were used for working of trains into the hands of the railway companies , and then furthermore except where specific agreements were entered into ( such as the GWR) , enabled the post office to request that such railway companies would carry its telegraph wires as required on the railway companies wires, subject to agreed compensation and as such the railway company would maintain them.

What in practice happened is that the railway company devolved such expansion and maintenance work back to the post office, and received in compensation for providing wayleaves and other rights , the transmission of such messages related to railway traffic free of charges , further more , the postoffice transmitted telegraphs for the railways companies overseas foc.

Hence as I understand it the actual poles ,used in the signalling of railways and telegraphs associated with their business , were removed from private operators and placed in the ownership of the railway companies , with the proviso that the railway companies would extend and maintain such posts and expand the system.

The railways benefitted under the act , in effect , as the private operators were nationalised , the railway was handed specific telegraphic structures allowing it to run its own system, subject to a requirement that they expand and maintain the network for the PO, and were compensated for doing so. in practice the reverse happened and the PO took over the maintenance, presumably instead of paying the railway companies to do so. As I said previously the railway companies had in effect either a specific or general contract with the PO

This was unlike the telegraphs laid alongside canals , where the post office took over directly the ownership of the infrastructure ( presumably because unlike the railways , the canal companies would have been perceived to have no technical ability to maintain such systems)
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby Andrew Waugh » Fri Jan 22, 2016 12:14 pm

madscientist wrote:does that mean that initially the signaller , looking to release the staff, operated his magneto , merely to ring the remote bell, then the remote signaller , also operated his magneto to provide answering bells , then held his key down and continuing to operate his magneto, until he saw his galvanometer swing vertical ?


Yes, that's exactly what it means. The magneto generated the current, then the bell key was operated to send the normal block signals.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Sat Jan 23, 2016 12:26 am

The reason I was asking this , is Im thinking of building a working version to add to a model railway , but as the staff wont actually go anywhere , I may have to invent a compromise instrument , I was thinking of marking the galvo with " normal (blocked )" , " train from" and train to " and in effect replacing the switch with form of commutator switch

after the bell sequence, offered the train forward , the remote commutator would be switched to " train from" , which with switch the local Galvo to "Train to " ( and technically release the section signal) ,, The section signal then would be locked again on being returned to normal until the remote commutator switch and local commutator switch were returned to " normal{blocked}" and the sequence began again .

I know its a form of conceit , but if the staff doesnt move , the W&T ETS machine is really just a slightly more complex " bell" !

in my case the remote signal box will be a computer, that in effect is monitoring a fiddle yard, if the incoming road is set to access a empty siding, the computer will on receiving line clear bell ( and send ack) , switch the commentator , so that the Galvo in the offering "box" , switches to "train to". when the train reaches the fiddle yard the computer will cause the offering boxes Galvo to revert to " normal".

equally when a train is departing the fiddle yard the reverse would happen, the computer will generate is line clear, and on receiving an ack bell and the human signal man, switches his local commutator to make his Galvo read " train from", the computer will then release the train from the fiddle yard ( The second part is a little more complex , but the automation isn't complex )

Ill make the instrument out of machined MDF, ( 8-10 " high ) all nice and red I have a CNC machine so I could even simulate the cast letters etc, well see , the Galvo is easy to mock up from a suitable centre acting meter movement


PS : all these machines had little brass knobs on the to of them , what was that for ?

Did cabins have different bells for each machine , I ve seen some pictures where there was a magneto per machine with a bell on top , and equally some with no obvious bells, was the bell inside the machine ???

Heres the actual ones Im interested in this box had five at one time ??, ( including two full size originally , Then four miniature on a shelf near the stove with two magnetos , ) the bells must be in the instruments??

Image

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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby Mike Hodgson » Sat Jan 23, 2016 9:32 am

madscientist wrote:The reason I was asking this , is Im thinking of building a working version to add to a model railway , but as the staff wont actually go anywhere , I may have to invent a compromise instrument


Hi Dave,

There is another approach to this problem you could consider, as used in Richard Pike's simulation of the Ely Dock Jn to Soham section (albeit using EKT rather than ETS). Ely Dock has a token instrument, and the signalman operates it in the usual way, but in instead of handing the token to the driver, he immediately inserts it into an auxiliary instrument, as he actually would at that location since the train stops a good distance past the box. In reality the driver would take the token from another auxiliary instrument near the signal. In the simulation however, that other auxiliary is at the Soham end of the section, adjacent to the main instrument which had accepted the train. After the train is deemed to have travelled through the section, the signalman transfers a token from his auxiliary instrument to his main instrument putting it back in phase. The same process works in other direction too of course, so the need to rebalance tokens isn't unduly frequent.


If you are computer simulating the far end of your section, you could simulate an auxiliary too. Richard simulates the train's passage as an elapse of time; in a model you could of course detect the train actually entering entering and leaving the section.


A much simpler technique I have seen used on a model railway was an OES Staff in the form of a small magnet which operators simply dropped onto the tinplate cab of the loco as it passed.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby Andrew Waugh » Sat Jan 23, 2016 10:16 am

madscientist wrote:PS : all these machines had little brass knobs on the to of them , what was that for ?

Did cabins have different bells for each machine , I ve seen some pictures where there was a magneto per machine with a bell on top , and equally some with no obvious bells, was the bell inside the machine ???

Heres the actual ones Im interested in this box had five at one time ??, ( including two full size originally , Then four miniature on a shelf near the stove with two magnetos , ) the bells must be in the instruments??


The brass knob was to raise the top of the machine to provide access to the innards. The top is hinged and secured with a lock. With the lid raised, a side plate can be removed to give access to the switchboard.

I've never heard of a ES machine with the bell inside - to be honest there is absolutely no room inside for anything like that. In Australia the bells were normally mounted on the wall above the machine.
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Sun Jan 24, 2016 12:12 am

I've never heard of a ES machine with the bell inside - to be honest there is absolutely no room inside for anything like that. In Australia the bells were normally mounted on the wall above the machine.


ah ha, yess I think your right , I have access to a picture that shows bells on the wall
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Re: Operation of miniature Webb and Thompson. ETS machines

Unread postby madscientist » Sun Jan 24, 2016 12:14 am

There is another approach to this problem you could consider, as used in Richard Pike's simulation of the Ely Dock Jn to Soham section (albeit using EKT rather than ETS). Ely Dock has a token instrument, and the signalman operates it in the usual way, but in instead of handing the token to the driver, he immediately inserts it into an auxiliary instrument, as he actually would at that location since the train stops a good distance past the box. In reality the driver would take the token from another auxiliary instrument near the signal. In the simulation however, that other auxiliary is at the Soham end of the section, adjacent to the main instrument which had accepted the train. After the train is deemed to have travelled through the section, the signalman transfers a token from his auxiliary instrument to his main instrument putting it back in phase. The same process works in other direction too of course, so the need to rebalance tokens isn't unduly frequent.


since the token doesnt travel , I see little point in that scenario of in effect just ,moving the token to an adjacent machine

thanks for the ideas though


I'm going to visit one of the last few operating ones in a few weeks

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