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Blog and Progress Updates
UkTrainSys plugin update; enhanced simulation of neutral sections and Automatic Power Control, neutral section test route released, and new screenshots showing improved Brecknell Willis Highspeed pantograph models and new sunset backdropsPosted by Anthony Bowden on 26th November 2010 at 9:25 pm
Firstly, I just wanted to say thank you for the positive reception with which the UkTrainSys cross-platform .NET plugin has been received; this was very nice to see! Based on feedback, I’ve now updated the UkTrainSys plugin, so that the AI driver will operate the Driver Reminder Appliance en-route. I’ve also implemented an enhanced neutral section and Automatic Power Control simulation, but first, a little background information might be in order…
Neutral section (phase break) installations
For those who don’t know, a neutral section (or phase break), isolates different phases of the power supply being fed to the overhead electrification system from each other. This is accomplished by inserting a short length of insulated material into the contact wire, which the pantograph head can still slide across at speed. In the UK, I gather these insulated sections are typically comprised of glass-fibre rods with ceramic collars threaded on to them, with the total length of the neutral section itself, being only around 4 metres.
At either side of the neutral section, are a pair of track mounted magnets, called APC (Automatic Power Control) magnets. Whenever an APC receiver on an electric train detects these magnets, the APC system flips the state of the air-blast/vacuum circuit breaker (ACB/VCB) between the pantograph and the on-train traction equipment, interrupting or connecting the supply from the pantograph and overhead line.
Thus, when a train approaches the first pair of magnets prior to a neutral section, the ACB/VCB is commanded open, such that there is no power being drawn from the overhead line when passing through the neutral section (this prevents the pantograph from drawing an arc and accidentally connecting one of the power supply phases to earth – the neutral section cantilever/support tubes are earthed so that the two separated phases aren’t connected in the event of an arc). When the train passes the second pair of APC magnets after the neutral section, the ACB/VCB is commanded closed again, and power from the overhead line can be taken.
See the illustration to the left, for an overview of the installation. The yellow arrow indicates the direction of travel; the red line indicates which parts of the contact wire are still live, even if the Automatic Power Control system has opened the train’s air-blast/vacuum circuit breaker, and finally, the blue line shows the location of the neutral section itself.
Updated UkTrainSys cross-platform .NET plugin (v0.3.1.3), with enhanced neutral section and APC simulation
Anyway, an updated version of the UkTrainSys plugin is now available together with the class 323’s 3D cab (version 0.3.1.3 – downloads can be found further down), and I’ve made some improvements to the simulation of electric trains. Firstly, I’ve modified the pantograph behaviour – when the pantograph is rising or lowering, pressing the Up/Reset or Down button has no effect until either operation is completed. Pressing the Up/Reset button when the pantograph is already raised, will just re-close the air-blast/vacuum circuit breaker (ACB/VCB) if it’s open.
Secondly, and more importantly, I’ve significantly improved the simulation of neutral sections, and Automatic Power Control. Now, the APC magnets and the actual neutral section itself can be declared separately. This means that every time the correctly defined APC magnet beacon is passed, it will flip the current state of the train’s ACB/VCB. This however, does not affect the actual availability of line voltage from the contact wire.
What this means, is that if the ACB/VCB is tripped open by an APC magnet, but your train stalls because you weren’t travelling fast enough, you can now manually re-close the ACB/VCB by pressing the pantograph up/reset button. If the train’s pantograph is not within the separately defined 4 metre long neutral section, you can take power from the overhead supply once again, and move the train backwards or forwards as appropriate, so you can try to build up enough speed in order to coast through the neutral section without stalling, this time. If the train’s pantograph does stop within the neutral section, then line voltage is not available, even if you try to re-close the ACB/VCB. In this case, you have to hope that your train is on a gradient, such that if the brakes are released, the train will roll out of the neutral section due to gravity. If this isn’t possible, then you have some explaining to do!
There is a more interesting aspect to this, though – with UkTrainSys, you can now drive backwards through a neutral section, not just forwards, and still have the full simulation experience. On a unit like the 323, (I think) the APC receiver is located on the bogie beneath the pantograph, on the second coach. The beacon receiver on an openBVE train is located at the front of the train, however – where the driver is (thereabouts). If travelling forwards, then when the front of the train passes an APC magnet beacon, this triggers a point-based event, and a check can then be performed, which will only carry out the ACB/VCB operation when the train is so many metres beyond the beacon; i.e the distance between the front of the train, and the location of where the APC receiver is supposed to be. But what happens if the train is travelling backwards? The location where the APC receiver is supposed to be, will pass the APC beacon before what is now the rear of the train (where the driver and openBVE’s beacon receiver are located), will pass the beacon, and hence trigger a beacon related event. This obviously won’t work properly, as the action triggered by the beacon, won’t happen until it’s beneath the driver’s position, which is too late when travelling backwards.
So, the UkTrainSys plugin now includes what I’m calling the “Offset Beacon Receiver Manager” (OBRM). Whenever the UkTrainSys plugin passes an APC magnet beacon while travelling forwards, the plugin stores information about the beacon in an array. The stored information includes the beacon type, it’s location, it’s optional data, and an offset distance which equates to the distance between the front of the train, and the location of where the APC receiver is supposed to be. The OBRM continually checks whether the train is currently travelling forwards or backwards, and whether the APC receiver location has passed the actual beacon location, taking direction of travel into account. When the trigger point occurs, the OBRM issues a command to the APC system, rather than doing this via the SetBeacon() method. The only other thing to mention, is that jumping to a station clears the encountered beacon history, so you actually have to drive forwards over a beacon for it to be stored by the OBRM.
This means that you can drive an EMU like the 323 through a neutral section backwards, but it also means that a Driving Van Trailer (DVT) with an electric loco pushing a rake of coaches from behind, can respond to the APC magnets at the correct time and location, whether travelling forwards or backwards, too.
Short neutral section test route, for use with UkTrainSys and the class 323 with 3D cab
I’ve prepared a short test route so that you can try this new feature. The route includes two neutral sections; the first on level track, and the second on an incline. Using the class 323 with the latest version of the 3D cab update and UkTrainSys plugin, you can drive through the neutral sections and play with the new behaviour.
On the first run, just pass through a neutral section as normal – it should seem pretty much identical to the neutral section experience in Network West Midlands, using Simon Gathercole’s BVE 4 UKMUt plugin.
On the second run, you can do things differently though – approach a neutral section slowly, and let your pantograph (where the APC receiver is located) pass the first pair of APC magnets, such that the VCB is tripped open, and then apply the brakes and come to a halt. You’ll note that the Line Volts indicator extinguishes, the VCB indicator light illuminates, and that you can’t take traction power – your train appears stuck. However, when the 323 has stopped, you can now reset the VCB by placing the reverser to Neutral and pressing the ‘2’ key – you should hear the VCB closing with a thud. Provided your pantograph is in contact with a live section of overhead line, the Line Volts indicator will illuminate again, and the VCB indicator will extinguish. Now you can take traction power. But what happens if your train is so close to the dead section of overhead line, that you can’t accelerate enough to coast through the neutral section, without stalling? You have to go to the external view by pressing ‘F2’, so you can see what side of the neutral section your pantograph is on, and choose whether to move the train forwards or backwards, such that you can take a “run up” at the neutral section, next time.
If you do stop with your pantograph in contact with the neutral section itself, then there is no line voltage, and resetting the VCB or lowering and raising the pantograph won’t change this. If you are on level track, your train is stuck there (you can cheat, and jump to another station, though). If however, you are on a gradient (the second neutral section is on an incline), then you can move the reverser to Neutral, and move the power handle to Off, and then release the brakes. Your train will now begin to roll backwards due to gravity (in reality, you would need permission from the signaller to do this). When your pantograph makes contact with a live section of overhead line again, the Line Volts indicator will light up, and you can take traction power again. If you continue rolling backwards, you’ll pass the APC magnet prior to the neutral section – this will trip open your VCB, despite heading away from the neutral section, and you’ll have to apply the brakes, stop the train, move the reverser to Neutral, and press the ‘2’ key to reset the VCB. Once done, you can take power, and go back as far enough as is required, to build enough speed in the forward direction to successfully coast through the neutral section.
Screenshots showing new sunset backdrops, and improved Brecknell Willis Highspeed pantograph models
Finally, I’ve been busy taking photos of sunsets again this week, and I just wanted to post a few more screenshots of the latest enhancement to the Cross-City South v2.0 and Watford Junction to Rugby routes. I’ve also, finally, got around to improving the Brecknell Willis Highspeed pantograph model, which now includes a full 3D pantograph head, with textures used throughout:
I hope you like the latest developments. 🙂