Thank you for your support ad excellent comment! 👍 The surging is cyclical and the potential for wheel slip being a causal factor is a most credible theory. 😎 Not all multiple unit combinations are affected by surging and it was not visible when the 4 CEP /4 BEP was coupled to the two 2H units (for testing pruposes). It may have been the power of three motors was sufficient to overcome the possible effects of a faster 4 BEP motor wheel slipping. 🤔 The wheel /rail interface is so often ignored in model rails - possibly be because it is an area least understood.....🧐

A fair request and honoured that people feel they can learn from my modest efforts - thank you! 👍 At present the layout is covered in detail on www.EwhurstGreen.com and a layout tour has always been in the back of my mind when a little more scenery is added. At the risk of being boring there is much to do before this can be done! 🤔 1. Until I can test all the diverging routes, crossovers, Platform 1 /Goods Loop (including adjusting the turnouts - solder construction) with trains running, much of the scenery towards the front of the layout has to wait lest it get damaged whilst leaning across with a soldering iron etc. 2. Whilst the Up and Down Mains are operational and all the turnout motors are in place and wired locally, the electric lever frame is not and (more importantly) to two racks of 60 number ex.GPO Type relays need to be put together. 3. Like that powering the 110 number relays that make the storage loops function, these relays need a substantial power supply on the scenic side (two 12v /10amp transformers) and I need to fit these in their own secure cabinet. However, the good news is the two Mercury Displacement Relays have now been installed ready for these power supplies (enabling the layout's power to be switched off from a single point). So please, bear with me and perhaps I need to consider a video of the layout as it currently is? 🙂

It is strange but also annoying! 🤨 We shouldn't have faults like this with *_Multiple_* units.....

Different characteristics from supposedly identical motors do indeed appear to be the underlying cause. The surging happens with a significant number of different units (but not all) when coupled together and regardless of direction of travel. The corporate blue units are visiting; I've number of green 4 CEP units of which some are affected. Other modellers are also experiencing this.

@@ewhurstgreen Thanks for your reply. It does indeed seem that motors are becoming very hit and miss in their quality these days. It's ok if your running single loco trains or units but not so good for consists and double heading etc etc. I still think your video highlights the issue admirably.

@@stretcheditsThank you for the compliment. 👍 Somewhere amongst the videos are two green-liveried 13-car Boat trains passing (MLV plus 4 CEP units) let alone many full-length CEP /HAP formations. 🙂 So, it is niggling when one formation is not operating smoothly. 😢 Just fortunate the UK railways did not use DPUs! 😲

Thank you for your interest! 👍 The surging occurs with both chipped and non-chipped units. 🤔 Mike at Model Railway Railways unlimited has suggested a capacitor on the slower unit and the fitting of a capacitor (or Resistor) to the DCC blanking plate (on order). ⚡ Now need to assess exactly how many of my units (green livery) have a speed disparity... 😉

If the above proves inconclusive (as I suspect) the only other thing will be to try and regulate the faster or slower unit by adding components. This will be quite hit and miss and rather fiddly. I might suggest a non polarized electrolytic capacitor of 47uF attached to the motor terminals of the slower unit, may be possible on the DCC blanking plug inside. This will give it a modest boost in speed. Let me know?

Mike, Thank you for your ongoing support - it is much appreciated. 👍 The blue /grey units aren't mine - just visiting. ⚡ However, I am aware a number of my units may be affected and if the faster units are the newer issue and the older units would need modifying then that would be an awful lot of units..... 😲 Need to get a few of mine out of the storage loops to look-see which are affected. However, we are currently talking about thirty Bachmann electric units including the MLVs. 😢 Not sure how easy it is to undertake motor swaps with my eyesight....🤔

Excellent reminder about the 9v battery - thank you! 👍 Seeking to avoid DCC as besides the cost, being visually impaired I'd struggle with the controllers.😟 Need to examine my (green liveried) units to ascertain the extent of the motor-speed discrepancy.🙂

Thank you for your support in respect of the video's conclusion towards the surging being related to supposedly identical motors operating at different speeds, but would back emf be a causal factor when surging occurs on pure DC (9v battery)...... 👍 The running of two uncoupled DC units on the same track is covered in the video and surging does not occur (until they are coupled). ⚡ Coupled DCC units do not surge as the 'chip' effectively acts as an individual controller for each unit. 🙂 The next question is towards a solution for DC running......🤔

Thank you for an interesting question! 👍 From Ewhurst Green electric trains would have run into Victoria. ⚡ Details on Ewhurst Green can be found here: www.EwhurstGreen.com 🙂 Details of all the Southern Electric slam-door electric units can be found on www.BloodandCustard.com Ultimately this is a Technical Video with units running under test. 😉

Thank you for your interest! 👍 The surging does not always occur with all combinations of multiple units. ⚡ The presence of a DCC chip in some of the units makes no difference. 🤨 However, surging does not occur when the chipped units (that otherwise surge on DC) are operated on a DCC controller. 🤔

Thank you for your interest! 👍 There has been some contact with Bachmann, who responded quickly with the suggestion of controller issues. However, a further response from Bachmann remains outstanding.😒

Thank you for your support which is much appreciated! 👍 The surging occurs across the whole range of speeds. Basic voltage monitoring was undertaken with minimal difference between two units running coupled (surging) and the two units running uncoupled (no surging). When coupled there is marginally more current draw (covered in Technical video 1). 🤔 It is outside by 40-years of experience as a career railwayman and most certainly needs the input of an electrical engineer of 40-years experience. 🙂 From the video you can see not all combinations of coupled multiple units exhibit surging and when I have run dissimilar locomotives together I've not witnessed surging..... 😯

@@ewhurstgreen Questions I may ask: Does it always happen in the same place on the layout, is that the straight section (ever noticed it on the curves), when run un-coupled but close together, do they run at roughly the same speed. Using an H&M controller is good as they are just a resistive machine with no clever bits. The interesting statement is that when the surging occurs the track voltage remains the same (is that correct?). I assume these Bachmann units have a worm drive and don't use "Pancake/ring field" motors favoured by Lima and Hornby of old?

@@andyknott8148 The surging is cyclical around the whole layout on both Up and Down lines, it not location specific and is not direction-dependant for coupled units. Other modellers have also reported surging. As detailed in the notes, it does not occur when uncoupled (this can be seen in the section of video @0.57 demonstrating the speed differential between the 4 BEP & 4 CEP). There is no significant variation in track voltage and the motors appear to be five-pole with a flywheel (bachmann-spares.co.uk/product/category/1099/class-411--4cep-emu-motor-31-425/e3142-206-01) driving via worm and gear tower.

Thank you for an interesting question.👍 I've not tested the haulage capacity of a Bachmann motorcoach - easiest way is for me to try seeing what an MLV can haul...🤔 The surging is not happening with all units - many of my own (green) units do not surge - as can be seen with the four number 2 HAP units in the video.🙂 In the first instance I'd suggest trying a pair of units (when able) to see if surging occurs. 🌞

@@ewhurstgreen Have you contacted Bachmann technical support?

Apologies: I didn't see the comment from archstanton5603!

@@PaulSmith-pl7fo Thank you for your interest! 👍 Yes, and their initial response was a controller issue (which is not the case) and they have not yet responded to a further exchange. 🤔

@@PaulSmith-pl7fo No problem - it is quite difficult to keep track of all the exchanges taking place! 😉

Particularly with *_Multiple_* units..... ⚡