Snapshot

Thanks, Keiron, that is very helpful in understanding how it works. My professional programming days ended 25 years ago so dabbling with NXT-G is about all I can manage now. I'll have to write a small test prog to make sure I have understood it correctly. Jonathan

Apologies for the late reply - been away for a bit. I'm already using the IRLink to control the trains and have been for over a year, albeit with an IR amplifier built by a friend as the IRLink's range is pathetic. The problem is that the layout and number of trains has grown such that I'm running into the limits of the number of sensors per NXT and the limits on cable length between sensor and NXT. I'd like to use Mindsensors' High Precision Distance sensors (if I can afford the six I need!) but I can only attach three plus an IRLink to each NXT. Mindsensors' sensor mux isn't powered so reduces the available cable length and, obviously, Mindsensors' sensors won't work with HiTechnic's powered mux. So the solution is to use two NXTs, one for each half of the layout and use Bluetooth to pass the single piece of info needed between them. I have been using home-made 'touch' sensors using reed switches that detect the train motor passing but they're a pain to make and mean permanently damaging two 2x4 plates, a 9V cable and a piece of RC track. I've made four but really don't want to make another six. I'm looking at light sensors at the moment as they're fairly cheap and I've seen Burf using one successfully on a train layout. The only hassle with them is that they need calibrating for ambient light before very use. Mindsensors distance sensors would be best but they're $70 each once shipping to the UK and taxes are added. This is still $10 cheaper than buying them from the only UK seller. There are added problems due to every PF motor being slightly different so stopping in a slightly different place but that's a story for another time.....

Sorry, that's totally not what I'm doing. The NXT is stationary and controlling the trains via PF infra-red and doesn't need controlling itself. The whole point of what I'm doing is that the layout runs completely autonomously. Probably does, Simon, as it's really just the protocol I'm trying to understand. As I said, I need to pass a logic value in one direction, to let the other NXT know a train has arrived at a station. If you do something like that in robotC would you need to pass the reset of the flag or would the receiving end just see that it was set when it got the next message passed to it?

Has anyone used BT comms between NXT bricks? I'm looking at it for my NXT-controlled PF train layout as I'm getting to the stage where I need either very long cables or multiplexors that won't take long cables. The code neatly breaks into two sections so using two NXTs is looking like a good solution. I just need to pass one logic value from one NXT to the other but can't work out from the block description whether I need to send the false value before sending another true. I hope this makes sense.... Jonathan

Prices on Bricklink are nothing to do with what it costs TLG to produce the item, they're entirely driven by supply-and-demand. A blue log costs TLG the same to produce as a reddish brown one so the price of any sets could be entirely affordable. But you're right that it would be rejected - it would need licencing and TLG won't produce add-ons to train sets after getting burned the last time it tried. Your containers are very good work though and I will be unashamedly stealing your colour scheme for the wagons. Jonathan

Here's my mixed passenger and freight train at STEAM last year. I reckon it's about 2.4 metres long and I could add another container wagon to take it up to 2.67. Jonathan

Problem with 'Export picture' - I'm getting an unhandled exception when I try this with just one or two .bbm files. I'm pretty sure it's something to do with editing or moving items in a text layer as it seems to occur after I've done this but freshly created files are okay. This happen with the same file under XP64 and W7 64. Alban, I have the details from the exception message available if you would like them emailed to you. Jonathan

It depends which Hobby Train model you mean. I've added PF to the number 5 loco and the number 22 train but I can't find a photo of it at the moment.

Thanks for the fast response. Fortunately I don't have any custom parts so I just extracted the files to a new folder then copied across the .config file and all my .bbms. Seems to be working perfectly now.

Alban, I've just loaded 1.7.1 over 1.7 (and the additional components) and get loads of XML errors when I start the program. Below is just one file and its error message. BlueBrick had encountered problems while loading XML files from the parts database. These XML files have been ignored. This problem may happen if an XML file contains syntax errors. Fix the syntax or delete the XML files to remove this warning. The file(s) concerned is/are: D:\User data\Jonathan\Lego\bluebrick\parts\Rail\2868b.0.xml 2868b.0.xml: Invalid character in the given encoding. Line 6, position 8. Looking at the XML I think the problem is the accented characters in the French desccriptions.

Another vote for 7939 here. I bought a 3677 and, apart from the little yellow MOW vehicle, wish I hadn't. I felt the loco was a very simplistic build with obvious cost-cutting in the dummy bogie and the rest of it is just forgetable. I'm not sure whether to ebay the unbuilt parts or add them to the bits box....

Part of the problem with the EN is the piston rods binding and there's an article in Railbricks issue 7 on how to improve them and other problem fixes.

And excellent instructions they are too and the inclusion of the XML file is extremely civilized. I have just two very minor comments - the trans-black panels and windscreen for the operator's cab haven't come out properly and 48 x 48 green baseplates will have to be light bley or light grey in the real world. I suspect there'll be world-wide shortages of things like yellow & black stripey tiles..... I'll have to upload the XML and see if I can afford to build this.

I've been working on NXT control of trains too. Have a look at this video to see what I had working six months ago. I'm using reed switches built into 2 x 4 plates to detect the train and an IRLink with amplifiers built by a friend. I've got points control cracked now and am going to extend the setup to several little shuttle trains apparently doing their own thing. I'm just hampered by not being able have a permanent layout....

The EN will run perfectly on the 9V track when motorised using Power Funtions. But you must make sure you're buying the correct motor as it does not use the standard train motor. As clcwong says, RTFM! The Maersk train uses a standard train motor (or two) and TLG recommends the rechargeable battery back which will also need a charger. The IR receiver is the same.....

No, never. The caboose is an entirely US invention. We had guard/brake vans instead. Most UK bridges are too low to allow something as tall as a caboose and imagine how much larger tunnels would have to be built. But I don't think locos as late as the one the EN is modelled on would need a brake van anyway.

You need to copy the HTML/BBCode from Flickr <a href=" title="DSCN0206 by Andrew G. L., on Flickr"><img src="http://farm8.staticflickr.com/7006/6503350549_e65957ef49_z.jpg"'>http://farm8.staticflickr.com/7006/6503350549_e65957ef49_z.jpg" width="640" height="480" alt="DSCN0206"></a> and edit it to get just the .jpg link http://farm8.staticflickr.com/7006/6503350549_e65957ef49_z.jpg Use the 'insert image' button and there you go

Email me and I'll send you the LDD file.

It certainly does although it's a bit longer than really necessary as it was intended for use with carriages. I have a another design that might look better as it's two studs shorter between the pivots. I'm sure I'd actually built two but I can't find them at the moment. <later> Just found the brick version and tested it - it's a stud too short. So here's what I hope will be the replacement. LDD only at the moment; will build it in brick later today.

No. I've run a 7938 with quite a few carriages and not had this problem. I suggest you try just pushing the dummy loco around to see if you can find what's making the noise.

Posted too late - points already covered.

It was never true, just a figment of your imagination. Either of the two PF extension leads should convert 8870 to 9V. As you say, it will be bulky.

I use this design with my 7938 variants: It's really a bit long for the 24-stud baseplates but it's the shortest that will fit and give enough clearance between carriages in the curves. LDD file available on request.....

Yes, that's exactly how to do it. When I've got restricted height in a loco so I can't stack PF connectors, I make a 'Y' cable that feeds both motors - one arm has straight-through wiring and the other has the centre pair crossed. Don't forget to insulate the joints so they can't touch each other.

Easy solution for the TXX - ignore it and put your Maersk cars on shared bogies. I've got a design I use everywhere I can as it saves two wheelsets and two buffers for every shared bogie. Reduced no. of wheelsets = lower friction = more cars in train.