Suzie

Times have changed now, back in the 1940s diesel was not a as an attractive option as now, and electrification was the only realistic way to modernise. The benefits of electrification would be efficiency (fewer locomotives required, fewer maintainence staff, better reliability...) and post war with lots of worn out locomotives just fit for scrap it was probably the best time to make a decisive move to modernise a key route and concentrate what was left on the lesser routes.

With long term stability (no threat of government interfering to spoil the long term prospects) there would have been the possibility of investing for the long term to reap the eventual benefits. Doing nothing was not going to reap any short term benefits!

You can use a DCC decoder, most have the capability to work on DC and will operate the directional lighting, and make use of the stay alive. The better the decoder the better it will work on DC so you really need to spend at least £20 and get a Zimo (MX600p12) or similar.

If you fancy having a go at making your own the DIY Decoder Project function decoder will do the job well and you should be able to make it fit in the 121 and fit a small capacitor after the rectifier to give stay alive capability. The directional lighting will then light correctly at full brightness as long as there is a small voltage on the track.

http://dccdiy.org.uk/function.html

In practice it is hard to get good results for directional lighting with stay alive on DC without using a computer to control the lighting so using a small PIC like the 12F629 used in the DIY decoder is a good way to do it, and operating the lighting on a lower voltage such as 5V means it can take a while for the capacitor to discharge before the voltage drops low enough to dim the lighting.

Of the big four only the Southern and LNER had active electrification plans in progress, so to say that the LNER would not electrify is a mistake since both the Great Eastern suburban and Woodhead main line 1500V DC schemes were in progress over a decade before nationalisation. Orders for a lot of mainline EM2s had been placed suggesting that a much larger main line program was going to happen on the LNER, the likes of which were not seen under BR(E) until 1985 after Woodhead had closed, some fifty years later.

That gives an example of how far back nationalisation put the railway, completely depriving it of justifiable investment. The LNER might have been short of a few bob, but it knew what it needed to do in order to become more profitable by investing wisely in efficient technology. The success of Woodhead and Shenfield would have enabled more finance to be available from investors and the LNER would have been on a roll electrifying Newcastle to York then to Kings Cross, and probably a whole lot more too during the '50s and '60s (but probably not the GC extension though).

I think that the Lenz can provide 300mA on the 'L' wire. Overload it and the Lenz will crash (this is what happens when you plug a Multimaus in sometimes due to the inrush). Probably best to run the whole layout Expressnet from a separate 1A 12V supply - use just the 'M', 'A' and 'B' wires from the Lenz and feed the 'L' and 'M' on the bus with 12V from an independent 12V supply. You will still have the 5-pin DIN socket on the front of the Lenz in case of emergency, or you can use that for the interface like you have done.

Not sure how many handsets can be powered from 300mA.

Was the USB interface connected by any chance? This I suspect will connect both the 'T' and 'M' terminals of the Lenz (they are electrically the same) to the 0V of the USB cable, and thence via the computer to mains earth.

1 hour ago, Northmoor said:

This is perhaps a key issue, that the (apparent or real) default policy of giving priority to passenger services needs to be carefully considered.

Do you delay a freight train so that at the end of a restricted passenger route, it misses the only available freight path for four hours and has to lay up in a loop until the driver runs out of hours, needs to be relieved by another driver arriving by taxi and the containers eventually arrive at the port six hours late (and possibly miss the ship, so delay the goods for days or even weeks)? 

Or do you delay 20-30 heavily-subsidised passengers on the Pacer by 10-20 minutes, which means one or two of them might miss a connection and will be entitled to a £50 refund from the industry?

Which is more important? 

This is where having plenty of capacity is key, and reintroducing a dedicated, or primarily, freight route would help things so the slightly incompatible traffic flows do not intermingle so much.

There must be some considerable value in removing freight from the Great Eastern main line having to cross all four tracks on the flat at Stratford to get to the North London line. The amount paid out when that goes wrong must be humungus - and it does go wrong... 

DCC decoders are available for these signals from Traintech for two signals and from Signalist for eight.

Bacon Factory Curve is one of those key new chords that in this case gets traffic from Felixstowe to March. Werrington gets it on to Doncaster in a roundabout way avoiding the ECML, now how to get it across the Pennines from Doncaster without getting stuck behind a pacer...

A new chord from the Goblin to Northumberland Park and reinstating the 4-track West Anglia (not sure that the existing Chord to Seven Sisters will be much use) will provide a connection from Thamesport and HS1 via LTS to March that will be electric as far as Ely so scope for a bit of infill wiring Ely to Peterborough to make a big improvement.

A few little things can make it all work.

7 hours ago, Lantavian said:

 

This isn't how transport planning works. First you identify sources of traffic, future demand, etc and then you work out what new routes and upgrades to existing infrastructure are needed to carry it. 

 

You don't start off by deciding that some old tunnels should be reopened and then try to make up new strategic routes to justify them re-opening.

 

That's why railway enthusiasts should never be allowed to run national transport policy.

I was thinking that the flows are already there - East coast ports and Europe to the Northwest and Northeast, all of which is currently carried on congested routes with limited capacity (ECML, WCML, NNL). As for future flow planning I am sure that much demand has already been told to go away because there is insufficient capacity. Sixteen miles of Woodhead, a few new chords, and a few miles reinstated across the open plains of Lincolnshire from March should somewhat boost capacity for freight and free up a good few paths on the ECML and WCML. I know that some parcels traffic could not be carried because overnight possessions on pinchpoints would make it nonviable - more alternative routes could see this type of traffic become feasible if diversionary routes are available.

I am thinking that there is probably a function button to switch off the inertia? F7 perhaps?

Saw a container train with 4x 86 on the front. Did not get a chance to photo or see if all the pans were up, but it was a nice prototype for everything moment and all four appeared to be in the same livery!

The duette has a split winding transformer, one winding used for the DC output and one controller, and the other transformer winding used for the AC output and the other controller.

'Wander' plugs were the plugs to use for this, and you can probably make 3mm plugs fit by opening them out a little. 1/8" is 3.175mm so not much bigger.

I think there might be a little opportunity here to 3D print a suitable plug based around 1/8" brass cotter pins. much like the originals were made.

On the LZV100 you could isolate the 'E' line from tripping the command station, if you can do this with the LZV200 as well you should be able to prevent Traincontroller from picking up the stop event because it won't see it. I have not seen inside a LZV200 to see how it is wired, but the 'E' line may be a physical connection that you could disconnect if there is no software configuration you can do to the booster in the LV200.

I like the Zimo ADAPLU PCB which makes it nice and easy to plug in a sound decoder.

They make one version with a 5V regulator on board so that you can power the servo to raise and lower the pantograph if you fancy having a go at a 313 as well!

As well as speaker, motor and loads of function connections there are track connections at both ends to connect to the bogies' pickups. Being a PluX socket it means that you can plug in any PluX decoder from an entry level £20 12-pin MX600 all the way up to a 16-pin or 22-pin sound decoder.

The PluX decoders are of a defined size (unlike the MTC-21 decoders) so you know that any decoder will fit as long as you allow the defined space.

Simple cheap multimeters are designed to read 50Hz sine wave AC (like the mains) and can neither read true RMS of a square wave or have a rectifier that will run at 10KHz. Thus you cannot trust them to read your track voltage. For this you will need a RRampmeter which is the inexpensive solution.

Different multimeters will give different voltage readings. The ones with slower rectifiers will read a low voltage. If you read the voltage further away from the command station it will read different to near the command station because the waveform will have been rounded off and appear more like a sine wave, but not enough to give an accurate reading.

You could make yourself a bridge rectifier from some fast diodes and use your meter on DC and get a pretty accurate result, you just need to know what voltage the diodes are dropping in the bridge so you can make an allowance.

The RMB2S is fast recovery with 150nS recovery time so is more than fast enough according to the Vishay datasheet.

You will need to use a series resistor. It sounds like your LED is of the red, yellow, orange, or wishy-washy green type and 3V will be too much for it without any current limiting.

Assuming that you would like to stick with your 2x 1.5V cells, and assuming that the LED forward voltage is around 2V, and assuming that a current of 20mA will give adequate brightness, I propose the following resistor using the formula R=V/I :-

((2x1.5) - 2) / 0.02 = 50R

Just connect a 50 Ohm resistor in series with your LED and power it from your two 1.5V cells.

I don't see why a new chord could not be built from the Victoria station site to Midland station. While it will not be free, I don't think it is going to be a huge cost in the grand scale of reopening a whole line. The satellite image does not exactly show the finest real estate in the area! A new chord has just been built in Manchester to do a similar job of getting passengers to the more sensible station.

Would it not be possible for Woodhead to be part of a strategic freight route from the east via March, Lincoln and Doncaster to Manchester and Liverpool avoiding London, East Coast and West Coast routes, where a relatively speedy passenger route with few stops would fit in well with non-stop freight for the trip across the Pennines. How much intermodal freight goes from France/Thamesport/Felixstowe/Hull to Manchester/Liverpool/Scotland?

The B40 will be fine, anything claiming to be ultrafast will be fast enough.

The DF005S will not be fast enough, this is designed for mains frequency operation.

Zimo make a selection of Next-18 decoders:-

MX618N18 for standard (non sound) Next-18 socket (should work in a Next-18S socket too).

MX658N18 for sound Next-18S socket.

MX659N18 smaller decoder also for Next-18S socket (but too big for a non-sound socket unless extra space has been provided and wiring is compatible)

If you have a spare output on one of your accessory decoders just use it to drive a SPDT latching relay (if it is a solenoid type decoder) or a normal relay (steady state decoder).

You can include this relay in the routes. You will either power the 4-track route, or the 2-track route.

Will you have signals? these can be interlocked too, and they will help your drivers know when they can go or not.

Ikcdab, What you have proposed will not work. I think you would be best either:-

• Use a double (or more) pole switch - the extra contacts in the switch replace the relay contacts.
• Use a pole of the relay to activate the servo driver board.

There are other ways around that you can switch the relay and servo controller with a SPST switch but the isolation circuitry and power supply requirement gets a bit out of hand and is really not worth the effort.

The base-collector junction of a bipolar transistor is a diode so when the collector voltage on the TIP121 drops below 1.3V you will start to charge the CDU capacitor (very slowly) from your 12V supply via the base-collector junction.

I don't think this is a problem that you need to worry about! It will only happen while the button is pressed and those currents are pretty small and hard to measure.

If a motor is 4 Ohms then to drive it from most DCC decoders which are 3A (obviously not the DCCconcepts ones which are high power) you will be limited to 12V, and there are not many situations when you will get reliable operation of either Seep or PL10 motors at 12V.

Yes working out the currents when a CDU is involved can be complicated, but simply the inductance of the motor limits initial current, and the discharge of the capacitor limits the end current, but in between when things actually happen the current will be very similar to the DC current.

5 hours ago, SimonBa said:

 

Thanks - I was hoping that since the action is momentary and the duty cycle is light I could get away without heatsinks.

 

The control panel PSU will also be driving LEDs route indicators via 12V (or 5V) latching relays taking their coil power from the output side of the diode matrix, so I was considering a separate supply from the CDU charging PSU.

 

Check my math? Assuming 4Ω for the motor coil, that gives 6A via the TIP, so 6mA minimum maximum to the base when hfe >=1000 and if supplied from a 12V supply that means the base resistor ought to be around 1k7 - 2k2 (with the 1.4V drop across the TIP from the CDU factored in). I was planning to use 1k5 1/4W resistors in this case. Figures dependent on motor coil resistance of course, hence the original question.

You won't need heatsinks.

Use 24V latching relays, they are readily available. It keeps things simple - one less PSU to have to worry about. Nowadays I usually use a single 12V PSU with an adjustable DC-DC step up to give me 24V, and I can wind up the voltage higher if I need it (sometimes need 35V with dodgy wiring and sticky points).

6mA is the minimum you want to the base, but you should be OK with a bit more. Not enough in this scenario is a bad thing because potentially the transistor will not switch fully on and will start to dissipate anything up to 36W (with typically 3mA drive), and you will only be seeing a quarter of the power at the point motor (36W instead of 144W). It is well within the transistors capability but not desirable. 2K2 will be too big at 12V, so 1K5 is excellent.