dibber25 Posted September 29, 2014 Share Posted September 29, 2014 In this issue: NEWS: CAD images of the Model Rail/Bachmann 'USA' 0-6-0T Two new 'Kings' promised Pendolino in 'N' Bachmann LNWR Coal Tank announced REVIEWS: Hornby 'P2' 2-8-2 Invicta Model BR 'CCT' Dapol 6w milk tank Bachmann track machines LAYOUTS: Eskmuir (OO) Loudwater (OO) Smithdown Road Junction (N) FEATURES: Derwent Valley layout plan by Paul Lunn George Dent re-jigs the Hornby Class 90 George Dent investigates the secondhand model market The Gresley 'P2s' Retro: The world of coarse scale WORKBENCH: Transform Bachmann's inspection saloon Improve Hornby Hawksworths Model autumn scenery REGULARS All the usual including Q&A, Show & Tell, Exhibition Diary, Backscene. Link to post Share on other sites More sharing options...
dibber25 Posted September 29, 2014 Author Share Posted September 29, 2014 October cover: Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted September 29, 2014 RMweb Gold Share Posted September 29, 2014 And a very nice issue it is too, thanks. Link to post Share on other sites More sharing options...
paftrain Posted September 30, 2014 Share Posted September 30, 2014 And a very nice issue it is too, thanks. I am a digital subscriber: where's my 32 page mini-mag? Link to post Share on other sites More sharing options...
dibber25 Posted October 1, 2014 Author Share Posted October 1, 2014 I am a digital subscriber: where's my 32 page mini-mag? That was a print-only purchase incentive. CHRIS LEIGH Link to post Share on other sites More sharing options...
Pint of Adnams Posted October 1, 2014 Share Posted October 1, 2014 A point of correction for this issue, which incidentally I purchased for the useful 'mini-mag'. In describing the Class 90s on p51 there is an explanation titled 'WHAT IS TDM?' This false history has annoyed me since it first appeared in the railway press and is now taken as gospel and regularly repeated and so this provides the impetus to try and correct it. TDM - time division multiplexing - with its companion statistical multiplexing are two techniques developed by the communications industry to maximise the throughput of data and digitally-encoded speech on trunk communications circuits. A modem provided a point-to-point individual connection, but it is obvious that there are not that many simultaneous individual circuits available in trunk cables. Rather than make a single connection across a circuit for the duration of a call, multiplexing provides for that single circuit to be shared by a number of simultaneous calls; the greater the bandwith and/or the compression used the greater the number of simultaneous calls that can be handled, with each chunk to be transmitted contained in a 'packet' which holds the origin and destination addresses and other management data. Time division means simply that each allocated connection receives in turn an equal time slice with all other connections, while statistical means that the connection carrying the most traffic gets allocated the largest proportion of the time available whilst it is sending. In the UK these techniques were applied to private company communications and data networks initially and subsequently adopted by BT for public networks, on which private circuits could be rented, under the marketing names Kilostream and Megastream. With regard to the transmission of other types of communications over the same circuits, this technique was employed in the types of communications described above with the total capacity utilised by dividing its available bandwith into smaller frequency bands to create additional circuits. So to go back to the MR article, TDM was not developed by BR but was merely adapted from an existing technology for a specific purpose. It's a parallel to the use of 'Carmine' in place of Crimson - some editor or writer thought that they knew better than the fact and created a false history that still survives and is perpetuated today. Link to post Share on other sites More sharing options...
sjgardiner Posted October 1, 2014 Share Posted October 1, 2014 Is it bad that I'm excited that I'll hopefully be able to buy this at Heathrow on Saturday while switching flights and actually get to read an issue close to the release date? Sounds like a good issue, i'm sure it will be. I only got Issue 200 at the newstand here in Toronto on Monday, so two issues in a week would be overload!! -Stephen Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted October 1, 2014 RMweb Gold Share Posted October 1, 2014 A point of correction for this issue, which incidentally I purchased for the useful 'mini-mag'. In describing the Class 90s on p51 there is an explanation titled 'WHAT IS TDM?' This false history has annoyed me since it first appeared in the railway press and is now taken as gospel and regularly repeated and so this provides the impetus to try and correct it. TDM - time division multiplexing - with its companion statistical multiplexing are two techniques developed by the communications industry to maximise the throughput of data and digitally-encoded speech on trunk communications circuits. A modem provided a point-to-point individual connection, but it is obvious that there are not that many simultaneous individual circuits available in trunk cables. Rather than make a single connection across a circuit for the duration of a call, multiplexing provides for that single circuit to be shared by a number of simultaneous calls; the greater the bandwith and/or the compression used the greater the number of simultaneous calls that can be handled, with each chunk to be transmitted contained in a 'packet' which holds the origin and destination addresses and other management data. Time division means simply that each allocated connection receives in turn an equal time slice with all other connections, while statistical means that the connection carrying the most traffic gets allocated the largest proportion of the time available whilst it is sending. In the UK these techniques were applied to private company communications and data networks initially and subsequently adopted by BT for public networks, on which private circuits could be rented, under the marketing names Kilostream and Megastream. With regard to the transmission of other types of communications over the same circuits, this technique was employed in the types of communications described above with the total capacity utilised by dividing its available bandwith into smaller frequency bands to create additional circuits. So to go back to the MR article, TDM was not developed by BR but was merely adapted from an existing technology for a specific purpose. It's a parallel to the use of 'Carmine' in place of Crimson - some editor or writer thought that they knew better than the fact and created a false history that still survives and is perpetuated today. I'm wondering if we're reading the same magazine? The text clearly says the class 90 was the first locomotive to be fitted with the TDM (based) system of remote control which had been developed by BR in 1979. It doesn't say that BR invented TDM - which it had of course been using in other applications since the early/mid 1960s - it simply says that BR had developed a system of TDM based remote control. I might be wrong but I've a pretty good idea that at the time BR developed the system no other railway was using a TDM based, two-wire, link for remote control of traction units however I am more than happy to be corrected on that point. Link to post Share on other sites More sharing options...
dibber25 Posted October 1, 2014 Author Share Posted October 1, 2014 I don't think that level of detailed technical description/history is relevant to a modelling article and the technicalities in the post lose me after the first sentence or two. I'm sure most readers would be equally lost. Pressures of space often mean that we have to be pretty strict with ourselves about how much detail we go into when speaking about prototype matters. My understanding - from Modern Railways, which I worked on at the time - was that TDM was a system which enabled the control 'messages' from DVT to loco to be transmitted via the existing electrical wiring in the passenger cars. I would not think that modellers need to know any more than that, and as far as I know it wasn't invented by any magazine editor. It most probably came in on a BR press release. Similarly, carmine is not an invention but a specific shade. The use of 'crimson' inevitably leads people to assume 'crimson lake' which is a far cry from the 'blood' colour of 'blood & custard' - a term which I banned from Model Rail during my Editorship as being as inaccurate as 'crimson lake'. Carmine and cream is known and understood by most modellers, be it technically right or wrong. CHRIS LEIGH Link to post Share on other sites More sharing options...
faulcon1 Posted October 10, 2014 Share Posted October 10, 2014 On a UK program shown here (Australia) "For the love of cars" a triumph stag was restored and painted in Carmine. So yes it is a specific colour not just a BR invention as i thought. By the way the car looked gorgeous. It's nice to know.....or not that the rivet counters are scrutinising the posts on here. Link to post Share on other sites More sharing options...
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