Of course it's possible to upgrade the 220/221 computer systems to 222-compatible equipment. Sure, it might not be a quick wiring job, but it's far from impossible. Class 460s weren't compatible with 458s either...
Also, to claim that trains built using the same bodyshells, bogies, etc. within 5 years of each other are "different generations" is ridiculous.
Except that the idea of adding electric carriages to 22x units came from Bombardier themselves! They came up with a fully costed engineering proposal (called "Project Thor") and were previously given "qualified approval" by the transport minister in 2011. Are you seriously claiming that you know more about the feasibility of the idea than the manufacturer of the train?
222s already have an electrical "bus" system so that electrical power is shared between carriages (EMT services run fairly regularly with one carriage not generating, I can definitely confirm that the traction motors still run on such carriages). Adding such a system to the 220/221 fleet would not constitute "rebuilding the train effectively from scratch". Bombardier's original proposal was for the 221 (although later proposals were drawn up for the 220 and the 222 fleets), so would have included the fitting of the bus system.
I appreciate your response to my post regarding this issue, however it is only fair that I respond accordingly to your comments.
Firstly, you speak of upgrading 220/221 to 222 compatible computer equipment but 222 computer equipment is also out of date and so compatible equipment could not be sourced for the 220/221, instead entirely new computer equipment would have to be fitted to the entire fleets. This is not simply a case of removing a computer and putting a new one in as a lot of rewiring would also be needed - you say possible, of course, anything is possible at a price, and it would be a seriously hefty price. My claim here was that "a SIMPLE upgrade would not be possible" you actually misquoted me as I never said upgrading would be impossible. I therefore stand by my comment.
Secondly, 220/221/222 are not built using the same bogies, 221 are tilt stock and so have totally different Y36 bogies, 220/222 however do share B5000 series bogies (B5005 from memory but don't quote me on it) - you seem however to misunderstand (may be due to my lack of clarity) what I meant by different generations (your description of my comment as "ridiculous" seems a little harsh), computer wise they most definitely are different generations, (consider a "new generation" iPhone, for example, basically looks exactly the same, but computer technology wise is totally different and some software and hardware will no longer be compatible) and the 222 was a seriously more developed product, clearly physically and mechanically the units are virtually identical. I also feel comparing to the 458/5 conversion, which was delivered extremely late, over budget, became increasingly complicated and seriously reduced the reliability of the units doesn't support your argument, again it shows it is possible, as is anything, but at a serious cost.
Thirdly, the "qualified approval" you mention of Project Thor; I do not think this is what you believe it to be, it is politician speak as the proposal neither qualified for anything, or is approved when it gains "qualified approval" status and to quote said Transport Minister at the time of granting qualified approval status, Justine Greening MP "I would encourage Bombardier Transportation and Voyager Leasing to look very carefully at reducing the capital costs and leasing rates, with a reasonable internal rate of return, as these proposals currently look very expensive". In other words, it is possible, as is anything, but clearly the work involved is so much it can not come in at a sensible budget, I therefore stand by my statement that, and I quote, "it will not happen". I should emphasise that I did not say Project Thor is not feasible, I even explain in simple terms the work which would be required. My statement that "it will not happen" is due to the implied cost of such work.
Fourthly, (i) the "electrical "bus"" system you speak of is not what you seem to believe it is. You are referring to the remote auxiliary supply by which a carriage will degrade its own 400v and supply degraded 400v to another vehicle. This indeed supplies an electrical bus but only one carriage can feed and only one can receive. It is clearly defined by rule which vehicle feeds which other when an engine is not running. This, however, is not the propulsion system and your claim that "EMT services run fairly regularly with one carriage not generating, I can definitely confirm that the traction motors still run on such carriages" is only partially correct as indeed EMT services (and XC and VWC) do run fairly regularly with one carriage not generating but I can categorically confirm that the traction motors do NOT run on such carriages, how can they? There is only a degraded 400v supply to the carriage. The traction alternator on these train types (locally engine driven) generates 680v 3 phase ac electricity, this passes through a bridge rectifier and is rectified to 875v dc to give a smooth supply to the traction inverter which inverts to between 0 and 567v ac depending on the traction demand being made by the driver. This system is self contained and there is no train bus carrying either 680v 3 phase ac or 875v dc through the unit. The degraded 400v is only just enough to keep the battery charger operating and the air conditioning pretty much functioning. Therefore to add a train bus for 680v 3 phase (probably) or 875v dc (unlikely) WOULD constitute "rebuilding the train effectively from scratch" (by which I meant stripping the solebar level down, installing a train bus and amending the traction alternators to feed the train bus and the traction systems to independently feed off of the said bus) (ii) while making this point you say that the units (220 and 221 included by the way, not just 222) "already have an electrical bus system" And in the same paragraph state "Bombardier's original proposal was for the 221 (although later proposals were drawn up for the 220 and the 222 fleets), so would have included the fitting of the bus system". This appears contradictory so I seek clarification, either there is or isn't a bus system in your eyes. (I can confirm that there is, but it is not for traction purposes).
For clarity therefore, the bi-modal drive system is indeed plausible, the diesel powered carriages would each have an alternator generating 680v 3phase ac feeding a train bus (which would need to be installed) and the electric vehicle (which needs to be built) would be fed with 25000v ac from the overhead line equipment and have a transformer fabricated to step down to 680v 3 phase ac in the secondary windings for the train bus and 400v ac in the tertiary windings for the auxilliarys. At this stage, considering the work being performed there could also be an option for feeding electricity back into the overheads when on electric mode from the electric carriage, which would require a different train bus for waste energy but would not negate the need for the roof mounted resistors as in diesel mode they would be required. I guess this is how you envisage it too? I just think it will be too expensive to implement especially considering the fact that the 22x series is nearing or is at half life.
I thank you for your critique.
