NIK

Hi, Chokes are an old word for inductors - they restrict or choke rapid changes in current. I think they have been included in DC model locos for many years to reduce the radio interference from the supply route to the motor. I've never seen the circuit diagram of a commercial DCC decoder but I guess the close proximity of a low impedance drive from the decoder is part of the reason the inductors (and capacitors) can be removed from locos fitted with DCC decoders. Also each DCC decoder has its own power reserve (a medium sized capacitor - not a stay alive) so even if there are interruptions in the pickups or wheels the decoder can often continue to drive the motor with a low impedance and reduce the radio emissions to an acceptable level. Although removing an inductor made of just a wire coil should make no difference to a DCC decoder (the motor has a much larger inductance), in recent years inductors with ferrite cores have been introduced and their characteristics vary noticeably with current and frequency. I could see this could potentially throw out the Back EMF feedback system employed by some decoders. I usually only remove the capacitor but as I learn more about slow running on DCC I may start removing the inductors as well. Regards Nick

Hi, I guess its difficult to put a decoder socket access hole under a Mk1 EMU or DMU due to trussing and other fine detail. DCC decoders have developed since I started DCCing my Bachmann Multiple units. I've still got a 4CEP that was fitted with an early Bachmann 21pin decoder. Its lack of advanced consisting causes problems when consisting and running a 13 car boat train on Beggarwood Lane (see RMWeb topic). I hope to fit my Mk1 EMUs with DCC controlled couplings so they may need a different decoder and possibly an extra decoder in the non powered driving car. On a more speculative front I hope to fit my EMUs with sparks effects by the pick up shoes whose sparks intensity and repetition rate varies according to whether the EMU is accelerating, coasting or braking. The Zimo range could facilitate this via its smoke generator functions. So I will probably retrofit my EMUS with Zimo budget decoders, probably the 21 pin budget decoder for Bachmann Mk1 EMUs. Regards Nick

Hi, I'd forgotten about the possibility of grease making things lumpy. I find taking the body to access the DCC decoder connector difficult even when I have lots of thin plasticard strips to hand. I will do some experiments possibly when its a bit cooler and I can venture into my model room. Many thanks. Nick

Hi, Does anyone know if the Bachmann OO 4 CEPs produced to date have a three pole skew wound motor or a five pole skew wound motor or something else?. I find it the 4 CEP a little bit coggy when coupling/uncoupling at slow speed compared to the Bachmann Class 25 but maybe its the difference in the gear ratios, the flywheel arrangement or the DCC decoders I have fitted. Regards Nick

Hi, I'm not sure if the financial problems of DJ Models makes the production of a Class 74 more or less likely. Unfortunately the only company with a chassis that largely suits the class 74 is Hornby with their Class 71 but they haven't gone in for small, short lived loco classes of late as far as I can recall. I'm not convinced by the photos I've seen of the body profile of the Silver Fox body of the Class 74 but I may buy one just to find out. I've found making very fine grills with thin surrounds a problem with scratchbuilding diesels. A technical solution for kitbashers might be a thin etched body wrap to be applied to a sanded down Hornby Class 71 body (with the pantograph well filled in first*). This might be cheaper than a 3D printed body that was of good enough quality to represent the grills and not show the printing steps/levels. * might be able to use the pantograph well to fit a diesel smoke generator in an attempt to represent the horrid looking black smoke the Class 74s produced on switching to diesel. I'd like a OO Class 74 for Beggarwood Lane (see RMWeb topic) so my layout group can run class 74 hauled trains up the 1 in 40 non electrified incline on the layout (probably slowly as the 74s only had a small diesel engine). I have a Hornby 71 which has a damaged gear train on one of the bogie gear towers so that may provide a source of parts (the incline is fitted with DCC Concepts Powerbase so a Class 71 chassis with only 4 wheel drive might be able to haul a reasonable length train once it is fitted with DCC Concepts Powerbase magnets). I also have a DJ Models Class 71 but that wont go round third radius curves and is too slow even for light engine moves. Regards Nick

Hi, Good news. I can't buy Model Rail in my town, any chance of publishing the details of the Class 11/12 models announced here?. Regards Nick

Hi, Do you know which model of DCC decoder is fitted to your train?. Regards Nick

Hi, So how does that quote from the Hattons website answer the question of whether the items are from another retailer or directly from Bachmann?. Regards Nick

Hi, To change the direction I think you operate a Double Pole Double Throw switch wired up to reverse the polarity fed to the Cobalt analogue IP. I guess the Cobalt analogue IP has diodes across the stop switches so that when the input voltage is reversed the stop switches are bypassed and the motor can move in the opposite direction (similar to the Fulgurex slow action point motor). Regards Nick

Hi, This may have been mentioned before: Hattons website: "Heljan 200xx VBA sliding door van in EWS livery O Gauge (1:43 Scale) £29.50 BARGAIN List price: £84.95" May be lower price on Hattons mailing list. Regards Nick

Hi, I forgot how free running some Bachmann 'EMUs' can be. I think the 4TC shares the same pin point axle box pickup system as the 4 CEP. I've tested the static friction of the 4CEP trailer coaches and got a figure of 0.75 grammes per coach - the lowest I've measured (the Hornby 4VEP trailers with was up to ten times higher per coach). Putting the friction values of 11 CEP coaches (3 REP trailers and 8 4TC trailers equivalent) and pull value for my 2-EPB** into my experimental gradient and curve predictor it indicates the 2-EPB powered REP should just haul two Kernow 4-TCs on the flat round 36" curves*. * as the static friction is so low in this case the friction due to the curve may dominate. ** I've assumed that the 2-EPB bogie will give as much pull in its new chassis as it did in its original - using the motor block from the 2-EPB may help. Good luck. Regards Nick

Hi, I don't know if you intend to haul 4TCs with your REP but from my tests on the pull force of 2-EPB power cars you might find it struggles to pull one Kernow 4-TC on the flat and might not manage two 4-TCs. Regards Nick

Hi, As part of selecting chassis for various multiple unit kits I've been doing tests of the top speeds of various modern designs of OO locos using a Bench Power Supply set at 12 volts. In most cases the top speeds were lower than the prototype. I've just tried a Gaugemaster series 100 controller instead and got a much higher top speed - just over the prototype. I then cranked up the bench supply until I got the same speed which occurred at 16.1 volts. Loco: Dapol Class 73 12V DC pre warm up : ~60mph. Left running for 5 minutes to minimise warm up effects differences: Gaugemaster 100 post warm up: 92mph. Bench power supply @16.1V DC post warm up: 93mph. Has anyone else noticed differences in loco top speeds between DC controllers or between DC and DCC?. Regards Nick

Hi, Yes, but can't forward and reverse trim (changed to keep the same ratio between forward and reverse) be used as an alternative multiplier to the speed table?. For example on the Zimo decoders change forward trim to 40 and reverse trim to 40 should give a top speed of 40/128 th of the top speed of the speed table. Regards Nick

Hi, I haven't tried the following but if you have a good DCC command station and low resistance wiring you could try: Set CV #57 back to default. Use CV#66 (forward trimming) and CV#95 (reverse trimming) as speed step multipliers. Regards Nick

Hi, I think just because the difference between the top of the speed curve and the bottom end is 65 it does not necessarily mean the decoder will only change the speed in 1/65 ths increments. It may interpolate the speed table into its own internal speed steps (from min speed to max speed) and then if in 128 step mode then may change the speed in 1/128th or 1/256th steps. As has been mentioned CV57 can be used as an adjustable speed divider. Regards Nick

Hi, Could you expand on what you mean by greater variation in the speed steps?. Regards Nick

Hi, The bidirectional spur is non electrified but it is intended that interregional passenger services could also use it including Brighton to Manchester and Clapham Junction to Kensington Olympia. There is going to be a position light (shunt signal?) on the post of the three aspect signal protecting the diamond (flat crossing) to allow entry into the freight reception siding. Thanks for the reminder about the interlocked ground frame near the flat crossing. Regards Nick

Hi Ian, I thought there should be trap points and a sand drag facing down the incline in case a conflicting movement was taking place across the crossing. I will have to consult Rob and Peter about how we can represent the safety features that would be present. I don't know of a flat crossing of this particular type on the Southern Region. There is going to be a signal on the incline to stop trains going down the incline before the crossing and a working ground signal in the goods yard protecting the crossing (see attached diagram - which was drawn before siding was added). The NCE Power Pro 5 Command Station we are using doesn't support interlocking but maybe we can locally interlock the points leading to the crossing to the appropriate signals and NCE routes. We are trying not to use JMRI for signalling/interlocking in order to keep things modular and because we are not sure of the reliability of the Raspberry Pi 3B - we have had a few times when the Pi 3B has not started into JMRI and has reported a PID error - I haven't been able to replicate the fault at home so far but I think it started after updating JMRI to the latest production version. Regards Nick

Hi, I forgot to mention that when I tested a run in Heljan Class 16 chassis with only one bogie driven the top speed was only 60 mph round third radius curves hauling 5 Bachmann CEP trailer coaches (the lowest friction coaches I've tested). With >3 foot curves and the same load the max speed was 70mph. So not quite the top speed of a 6 car Hastings unit. However there may be space to fit a different motor (which would have to be more powerful and possibly faster under load of 5 coaches going round curves). I've bought a Faulhaber coreless motor with a higher top RPM that will fit in the motor mount of the Class 16 but as I'm starting with motorising Tadpole kits its not a high priority to fit and test it*. * the run in Class 16 chassis with only one bogie driven had a top speed of 72 to 76 mph round 3rd radius curves when hauling two CEP trailers - so probably will suit my requirements for a Tadpole (I can run my stock on a roundy roundy club layout). Regards Nick

Hi, The photo appears to be of a Hastings DEMU of which there were three types 6S, 6L and 6B. Worsley Works make Sides, ends and floors for the Class 202 and Class 203 (6L and 6B) but not yet for the Class 201 (6S). I haven't bought any yet so I don't know what the quality is like. The roofs might be a problem as they are possibly narrower than standard Mk1 coach roofs. I'm hoping to use one end of a Heljan Class 16 chassis for my Hastings and Tadpole DEMUs as most of the chassis is narrower (see attached diagram). Regards Nick

Hi Mike, Yes, there is a crossover that links the non-electrified spur that uses the incline to the reception road for the goods yard (see attached photo). It doesn't get much use at club open days at present as since when the layout was designed we have gained new members who are more interested in block trains which they run on the mainline and are also reluctant to fit Spratt and Winkle Couplings for which magnets were fitted in the goods yard. The plan was that freight trains arriving down the non-electrified incline would go into the reception road and a shunter from the goods yard would take the train into the goods yard, releasing the train loco to go into a short goods yard siding or go to the refuelling siding There are four* routes allocated on the layouts NCE Power Pro 5 DCC system that use this crossover (*two reception sidings and two tracks on the mainline- clockwise and anticlockwise). There is going to be a signal on the incline so that trains including freights leaving the goods yard can be held if the mainline is not yet clear. Regards Nick

Hi, Just out of interest my Bachmann Mk1 64' coaches weigh about 160 grammes and have metal axles on plastic axle box bearings. A friend has used a pin point axle reamer to improve the running of his Bachmann Mk1 coaches and bogie vans. I had a semi automatic layout which I ran for hundreds of hours as a teenager and eventually the plastic axle box bearings on the Palitoy Mainline coaches got very elongated. I would like to mention that using solid loads in wagons that might have the side effect of noticeably increasing the weight of the wagon may cause problems if you ever run the wagons on a layout with gradients. Regards Nick

Hi, Beggarwood Lane performed quite well at our clubs last open day on the 13th April. The club has gained three members so far as a result of the open day one of whom is coming along on the same night as Beggarwood is being worked on. The bidirectional line in the fiddle yard was used in anger for the first time using multiple units. The bidirectional line can be used to get trains that have gone up the incline onto the clockwise circuit into a siding where the train can be reversed. However loco hauled trains currently need the loco detached and moved to the other end of the train. There is little space for a reversing loop. DCC controlled uncouplers on the locos would help or maybe uncouplers at one end of the bidirectional track. A route via a loop that can only be accessed from the furthermost track in the fiddle yard has been added. Wifi control using smartphones has been added although we couldn’t control the NCE routes from the Android Engine Driver software. Its looking a bit tricky to control the NCE routes via JMRI’s Wifi service. Work on Beggarwood Lane is continuing to ramp back up after the Great Model Railway Challenge. Some extra bits of static grass have been added on Board A, Board F has been having a fine sandy scatter added. Stuart has been putting in more trunking. The rail location cabinets (relay boxes) have arrived and have been cleaned up and sprayed with primer. Some came with cables coming up the side of the box. We have been advised this cable is the signalling power supply and goes inside the cabinet to a power converter. We’ve been told where there might be say four cabinets together one may have the cable up the side. The first holes have gone in for the Infrared sensors for signals and the two speedometers (see attached piccie). Unfortunately one of the holes is a bit close to where a Infrared detector is going in for third rail sparks from a downramp. It was difficult to use the same detector module to do both signal sensor and third rail sparks sensor and still have a standardised MERG module for the signal sensors which are the more important feature. Also in some locations there is no signal nearby to share the Hector2s two sensors about and also a limited number of Hector2s. We intend using five Heathcote Electronics IRDOT unit which didn't get installed on our previous layout. The third rail sparks unit detects strong reflections off a strip of aluminium foil lined up with the third rail picks on the loco/train. The MERG Hector2s are designed to detect weaker reflections off the dark underside of trains. Hopefully the Infrared Detectors being about 30mm apart wont cause any problems. The most likely problem is that the more sensitive Hector2 gets retriggered very shortly after the train gets to the third rail flash sensor (sending back a strong reflection). That should only extend the 1.5 second pulse from the Hector2 a tiny bit. It may be possible to link the signal sensor to the third rail flash unit so it doesn't start transmitting IR before the train gets to the signal sensor. As the point where the third rail flash unit is on a bidirectional bit of track may stop the off ramp flash triggering unrealistically when a train is going in the reverse direction. A MERG Hector2 dual Infrared detector module is going to be tried for a combined signal sensor and twin sensors a shortish distance apart for one of the speedometers. There are signals each end of the long straight so sharing those signal sensors with the speedometer circuits is ideal if it works. Regards Nick (member of the Basingstoke and North Hants Model Railway Society – still looking for new members)

Hi, The track passed the coin test, is there a way of testing if a DCC Command Station is acting fast enough?. Also shouldn't the RTR trains should be designed to cope with DC supplies (that can have slow acting current limiters)?. The Heljan OO Class 128 Single car parcels units I bought for their chassis have wiring from the pickups that seems even thinner than that fitted to the Hornby 66 that burnt out its wiring. Regards Nick