A single line token or train staff contained in a pouch with the larger ring form handle to make it easier to pass between signaller and crew without dropping it.
Girvan, South Ayrshire
I don't think matchmaker was asking you to name the station. More likely complaining about "train station".
Judging by the speed it's going as it passes the 'box and the acceleration after the re-start, that was a 'lets get the hell of town' bit of driving that didn't quite work outNon-stop exchanges being particularly entertaining for the observer
The line between Girvan and Stranraer is well known for being the last main line use of tablet working in the UK with the equipment dating from the 19th century. Elsewhere Network Rail metals use the later "token" system. Although functionally the same a "tablet" is a round disc whereas a "token" tends to be more staff or key like.
Judging by the speed it's going as it passes the 'box and the acceleration after the re-start, that was a 'lets get the hell of town' bit of driving that didn't quite work out
(Nice bit of Alco 251 diesel thrash too...)
In some places there have been 'auxiliary' token machines directly accessed by train crew for decades, going back even before BR. They might be located in a cabinet on a platform like this, or at the end of a goods loop, so the signaller (or crew member) doesn't have to walk possibly hundreds of yards to issue or collect a token for certain movement sequences for which the box is at the wrong end of the station for example. In this case, the token is released remotely by the EMCC (East Midlands Control Centre). On the Central Wales line, all the intermediate crossing loops have token machines in platform cabinets operated by the train crew. An unusual feature of that line is that the tokens, while clearly interlocked with each other as necessary to ensure only one can be out of a system for a particular single line section, the keys are free to be removed (if safe) without a release being given by the signaller, although verbal authority by telephone must be obtained for each withdrawal. In this system, engineered in the cash strapped 1980s, the machines at opposite ends of each section were originally linked by leased private BT lines to avoid having to provide cabling alongside the whole line as a replacement for the old aerial pole route. A safety-certified FDM (frequency division multiplex) 'Reed' system operating at audio frequencies carried multiple bits of relay state data across each BT link.
I don't know about that, but in addition to the distinct section names engraved on the tokens, Tyers key token, the most common type in UK today, are configured to one of four patterns that cannot be inserted into a non-matching machine. All machines in a particular signalbox must be of different configurations to avoid the risk of a signaller mistakenly placing a token in the wrong one. The key ends have slots cut in varying positions to distinguish them from their neighbours. Identified by the letter code, a view of each configuration looking along the key from the handle end is illustrated below, showing the relative positions of the slots that engage with corresponding pins in their matching machine. The modern cast tokens are painted distinct colours according to their pattern: A = red, B = blue, C = green, D = yellow.
None of that would have prevented Abermule. The token was never put in the machine. The porter who collected the token from the driver gave it, in its pouch, to the stationmaster to replace in the machine. The stationmaster thought the porter had already done this, and that he was being given a token for the next section that the porter had just taken from the other machine. In fact no-one had been in the machine room since a third person, unbeknown to the other two, had operated the release for a token to be retrieved at the other end of the single line section, allowing a train coming the other way into the section and preventing another token for that section being released.
Agreed. The final point is the critical one in my view, as a token needs to be withdrawn from the appropriate machine for the associated block signal lever to be released electrically to pull, so if there's an incoming train just arrived from the same section, that one's token/tablet must be inserted first to put the system back in phase for the subsequent withdrawal. Later circuits also enforce a 'one pull' feature, so if the block signal has been cleared already but needs to be replaced to danger for any reason before departure, the token must be run through the machine again in cooperation with the signaller at the other end of the section in order for the signal to be released again. All actions logged in the train register of course. Just as today, the cumulative improvements in system and procedural safety were built on the findings and recommendations of accident investigations over decades.
The tablet equipment is not in the signal box at Barrhill, it is within the station office on the Platform along with the GSM-R telephone where the signaller spends all his time unless exchanging tablets with the driver or pulling off signals.
It wouldn't give more flexibility, it'd reduce it. An RETB-fitted unit can work over the Stranraer line under the current signalling - it doesn't need any special equipment fitted to the train.
