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AC Electric early cab Color


Evertrainz
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Hi all - 

 

I've been struggling trying to identify the cab interior colors of the Class 83 cab as-built, in Electric Blue livery. I am aware that the "standard" Pilot locomotive cab color scheme was green for the bottom half, and cream for the top half. However, electrics seems to have substituted that green color for a more grey-ish color, that has a tinge of blue-green to it. The following pictures will demonstrate what I mean. It also seems to be prevalent in Class 73 locomotive cabs today.

 

Class 85 cab (rheostatic braking switch behind power panel): https://www.flickr.com/photos/kerryp28/6117010213/in/gallery-125881805@N02-72157711442485136/

Class 83 cab: https://www.flickr.com/photos/14581588@N05/3512890881/in/gallery-125881805@N02-72157711442485136/

Class 73: https://www.flickr.com/photos/brianews/5863664855/in/album-72157627030673260/

 

 

 

With this in mind, I have some questions.

1. Would anyone know if the color of blue-grey used for the control desk in the above shots is 'duck egg blue'?

 

2. Does anyone how the 25kV AC Electric cabs were originally painted? I would assume that they were painted in a similar pattern to the diesels, where the cream and green portions wrapped all the way around the cab through to the bulkhead, however many shots show that the bulkhead is indeed painted white. https://www.rail-online.co.uk/p1024248118/e2fb64802

 

3. Was the roof painted white, or was it painted cream?

 

 

I've looked at all the pictures I can, and things are still inconsistent; for example, in the 25kV AC edition of Modern Locomotives Illustrated, a works shot from 1959-60 shows three AL1s (81s) being completed, and all have their doors open, showing the bulkhead clearly. On all three, the pattern of bluish-grey and cream is followed, with cream on top. However, in shots of other early AC electrics, the bulkhead is white, similar to the shot of E3304 above. 

For the AL3s/83s, the only things I can say with confidence is that the control desk is bluish-grey (duck egg blue?), the windscreen is cream, and the draught screens behind the driver and secondman are cream. The bulkheads are white aswell.

 

Any help or information about how locos were painted, or conventional schemes of the 1960s, would be very helpful. I've attached my crude attempts at illustrating what I've got so far. (The very first one has the cab interior ceiling also painted cream, but the following three shots have the cab ceiling painted white. Which one looks more correct?)

 

Thanks and regards

Ron

 

 

AL3_1960s_cab_R9.jpg

Cab_1.JPG

Cab_2.JPG

Cab_3.JPG

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I know the colour as “duck egg green”, although whether that is its official name I’m not sure - It probably comes from BS381c if you want to check.

 

It was very widely used in industry, especially the electrical industry, for control panels in the 1950s-80s, and is sometimes still used, even in VDU control displays, because it is very restful on the eye, and because it acts as a very good neutral Colour against which other colours are easy to distinguish.

 

I think it became popular after it was used for aircraft instrument panels during WW2.

 

PS: try BS381c - 210 ‘Sky’ (not BS381c ‘Sky Blue’, which it definitely isn’t)

 

 

Edited by Nearholmer
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Those interior representations are excellent. 

 

Further along that sequence of photos on rail online, there's a close up front offside 3/4 shot of AL4, E3036 repainted rail blue, syp with the nearest cab door open - as the external cab roof is very clean white, the bulkhead is certainly not white - appears very light grey with a hint of lavender I would say (however the usual caution with blue colours in photos - there's a shot of an early loco in electric blue with part of an 86 in view (rail blue) - they look more similar than they should)! It's the same bulkhead colour as in the photo of E3304 (and what an amazing photo that is). I think yours is too blue in comparison - it's more of a very pale grey with a hint of lavender in the photos. Also in the sequence is a shot of E3098 with the cab door open but looking from behind and from rail level - part of the interior cab roof is clearly visible though it's a little dark. You'd need to enlarge it to see properly but it's possibly the same colour as the bulkheads.  

 

In the Flickr shot of E3030 where the desk is in clear view, the cab side in the driver footwell can be seen (unless it's all part of the desk moulding) - it's the same duck egg blue as the desk. Also there appear to be some areas of the cream area around the cab windows which look cleaner and more white than others. That cream is possibly a creamy off white colour. Did the off white used wear to a cream colour? (eg it looks like white with smoke staining). 

 

There was also at least the loco number on the centre interior cantrail - possibly additional lettering. 

 

Would it be worth a look at a preserved one (or see if the ac loco group have any photo records)? 

Edited by MidlandRed
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On 29/07/2020 at 01:09, Nearholmer said:

try BS381c - 210 ‘Sky’ (not BS381c ‘Sky Blue’, which it definitely isn’t)

 

On 29/07/2020 at 19:47, stovepipe said:

Though AL6s these may help in some way. Skip to 10:20, 11:17 and 11:24 ...

 

Thanks guys - I have updated the desk/bottom band color to a desaturated shade of that duck egg green. The video confirms that indeed it was possible for the cab roof to be a different color from the front windscreen and driver side paneling. 

 

On 29/07/2020 at 04:54, MidlandRed said:

I think yours is too blue in comparison - it's more of a very pale grey with a hint of lavender in the photos. Also in the sequence is a shot of E3098 with the cab door open but looking from behind and from rail level - part of the interior cab roof is clearly visible though it's a little dark. You'd need to enlarge it to see properly but it's possibly the same colour as the bulkheads.  

 

The roof/backhead was actually a flat grey color with no bias towards one hue, but the lighting of the scene made it appear bluish-grey. I have changed it to the ever-so-slight lavender hue of light grey, and I think it looks fitting. I've attached a couple shots that show the very slight difference between windscreen color and cab ceiling/roof - am I making this up or does it look correct? :D  Also hopefully the first one confirms the problem of original color - it's indeed a very strong hue of yellow, rather than cream, and it actually wore to an off-white with time. 

 

 cabroof1.jpg.eeda93680db88f0d5a16ead90985fe1c.jpgcabroof2.jpg.27469d0196976c984055866b4b47f410.jpg

 

 

The note about cab reading at least loco number, along with cab end and MPS, is confirmed - E3062 seen below. 

 

Cab_E3062.jpg.bf405d99df459743306b0168ac4f28b1.jpg

 

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I've linked here a collection that is likely no stranger to RMWeb :P  This shot shows a more representative view of the cab desk color on E3050: https://www.flickr.com/photos/93456400@N04/15734898347/in/gallery-137057962@N02-72157695215009780/

 

The rest of the shots in that Flickr collection show similar views of the other AL- classes in the lineup. Here, we can see that the AL4 has white (or grey-lavender) draught screens, while it appears to be cream on the other classes. Similarly, the AL1 has the split between cream and duck egg green on the rear bulkhead, while none of the others do.

 

Also attached below is my attempt at a more 'proper' coloration. Critiques welcome.

 

AL3_1960s_cab_R10.jpg.7571e0c8c8b42b0d19bdcd6f7493f8f6.jpg

 

 

 

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http://www.dawlishtrains.com/driving-cabs-electric-loco.html

The more I look at it, the more I think that the Class 83 cab shot on this site is from English Electric's Vulcan Foundry, the interior unpainted. The relatively shoddy finish gives it away, as do the unpainted steel strips.

 

 

This link has a nice video that is useful to early AC traction modelers, and the end has a decent clip of a cab ride in an AL3. The interior there looks finished and very neat indeed. 

Again going back to the interior, the roof section looks to be a noticeably lighter color than the windscreen and side panels of the cab. 

 

 

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On 31 July 2020 at 01:26, Evertrainz said:

I've linked here a collection that is likely no stranger to RMWeb :P  This shot shows a more representative view of the cab desk color on E3050: https://www.flickr.com/photos/93456400@N04/15734898347/in/gallery-137057962@N02-72157695215009780/

 

The rest of the shots in that Flickr collection show similar views of the other AL- classes in the lineup. Here, we can see that the AL4 has white (or grey-lavender) draught screens, while it appears to be cream on the other classes. Similarly, the AL1 has the split between cream and duck egg green on the rear bulkhead, while none of the others do.

 

Also attached below is my attempt at a more 'proper' coloration. Critiques welcome.

 

AL3_1960s_cab_R10.jpg.7571e0c8c8b42b0d19bdcd6f7493f8f6.jpg

 

 

 

 

I think this is about right. I would return to your original desk colour but much lighter - it's definitely blue not green (of the duck egg variety). These models are fabulous btw!! 

 

Ive been a fan of the WCML and especially the various generations of AC electric locos - this stems from being taken as a child by my parents by car to watch these locos pulling trains at speed at various locations on the Trent Valley section of the WCML. Two particularly notable experiences were the appearance of E3108 on a northbound express at speed near Tamworth - I didn't even know they existed and first impressions were the set back loco numbers, vertical lower cab (rather than the rake back of the whole front of the earlier locos) and the different shade of blue, which was very noticeable in the afternoon sun. The second was being shown around the cab of E3019 one evening at Stafford - it was parked in one of the down slow/local platforms - this was an amazing experience for me as a train-mad child and although I have various AL6 marked with C and E3036, I only remember E3019.

 

This was all probably 1964-5 when the southern changeover point to diesel was first at Nuneaton, then Rugby. 

 

The WCML was definitely the pinnacle of modernisation at the time, and in quantity and especially after completion to Euston and Birmingham. 

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  • 3 months later...

Would anyone happen to know: 

 

1. what horns the Class 83 had (Desilux? westinghouse? hyson airchime?) or if there is a sound recording of one out there anywhere

 

2. what the single white air brake hose cock was for, when built; could someone confirm that this was for when being towed by another loco to charge its own reservoir/apply brakes? Why did some locos have two of these white cocks instead of one?

 

3. (for drivers) how often was the "maximum power" of 4400 hp reached, or on any AC loco in general? Sorry, I don't have a good understanding of AC lines and how that works. Was it when the OLE was supplying more current than usual due to lower traffic? Accounts of Alan Varley recorded 81017 clocking 114mph on one instance in the late 70s. If this is true, then the Class 83 would be the most powerful BR locomotive produced by English Electric by a handy 1100 hp (take that, Deltic bashers ;) )

 

83_R24.jpg

 

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1.  Don't know about the horn type

 

2.  I suspect the white painted buffer beam pipe may be the discharge point for the on-board urinal rather than anything brake related 

 

3.  A complex subject, even more so if you don't understand how electricity works.  In simple terms the current consumption of a DC motor reduces as the motor speeds up so maximum currents are seen at starting and low speeds.  Total current in the ole is related to demand so light traffic equals low current demand and vice versa. 

 

In terms of power output motors have a continuous rating and a short term rating.  As the name implies they can operate at the former continuously whilst they can only operate at the latter for a limited period, typically an hour.  Normally for an electric locomotive the continuous rating is quoted so for a Class 83 that was 2950hp but its short term rating will be higher (I can't lay my hands on what it was at the moment but probably at least 3600hp).  The motors in the deltic are very similar to that in the class 83 (unsurprisingly as both were EE products) and also have a short term and continuous rating but the deltic has a huge constraint in that the amount of power that it is capable of supplying to its motors is limited by the installed engine power.  The class 83 also has a constraint as there is a maximum amount of current that the ole can supply and a maximum amount of current that the locomotive protection circuits will allow it to draw.  But the 83 will readily be able to produce power outputs above the continuous motor ratings if the situation demands (albeit only for an hour) but the deltic won't. 

 

So on paper the deltic is more powerful (as electrics usually quote continuous rating) but in fact the 83 was capable of producing more power under certain conditions

Edited by DY444
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The shape of an electric locomotive's tractive effort and power at rail curves are very different to that of a diesel locomotive. The TE available remains constant up to the limits DY444 has outlined, with the power at rail increasing with speed to this point also - which usually occurs above 40 mph, compared to below 20 mph for a diesel locomotive from the same era. Beyond this point, power at rail and TE declines as the back emf of the dc traction motors increases and the stages of field weakening takes place. The continuous rating is somewhere on the declining part of the power and TE curves determined by the amount of cooling air that can be provided and the amount of back emf current that can be dissipated continuously, which are constrained in part by the physical space available inside the locomotive for fans and resistor banks.

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11 hours ago, DY444 said:

1.  Don't know about the horn type

 

2.  I suspect the white painted buffer beam pipe may be the discharge point for the on-board urinal rather than anything brake related 

 

3.  A complex subject, even more so if you don't understand how electricity works.  In simple terms the current consumption of a DC motor reduces as the motor speeds up so maximum currents are seen at starting and low speeds.  Total current in the ole is related to demand so light traffic equals low current demand and vice versa. 

 

In terms of power output motors have a continuous rating and a short term rating.  As the name implies they can operate at the former continuously whilst they can only operate at the latter for a limited period, typically an hour.  Normally for an electric locomotive the continuous rating is quoted so for a Class 83 that was 2950hp but its short term rating will be higher (I can't lay my hands on what it was at the moment but probably at least 3600hp).  The motors in the deltic are very similar to that in the class 83 (unsurprisingly as both were EE products) and also have a short term and continuous rating but the deltic has a huge constraint in that the amount of power that it is capable of supplying to its motors is limited by the installed engine power.  The class 83 also has a constraint as there is a maximum amount of current that the ole can supply and a maximum amount of current that the locomotive protection circuits will allow it to draw.  But the 83 will readily be able to produce power outputs above the continuous motor ratings if the situation demands (albeit only for an hour) but the deltic won't. 

 

So on paper the deltic is more powerful (as electrics usually quote continuous rating) but in fact the 83 was capable of producing more power under certain conditions


Thanks for that, makes a bit more sense but I’ll still have to spend some time wrapping my head around it :D

 

Stupid question, but Under what condition was the continuous rating based off?

 

83s had a short-term rating of 4400 hp. The 82s maxed off the “roarers” at 5500 horsepower.

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5 hours ago, stovepipe said:

The shape of an electric locomotive's tractive effort and power at rail curves are very different to that of a diesel locomotive. The TE available remains constant up to the limits DY444 has outlined, with the power at rail increasing with speed to this point also - which usually occurs above 40 mph, compared to below 20 mph for a diesel locomotive from the same era. Beyond this point, power at rail and TE declines as the back emf of the dc traction motors increases and the stages of field weakening takes place. The continuous rating is somewhere on the declining part of the power and TE curves determined by the amount of cooling air that can be provided and the amount of back emf current that can be dissipated continuously, which are constrained in part by the physical space available inside the locomotive for fans and resistor banks.


Thanks, I’m taking a physics course next semester that details EMF and general circuits so maybe I’ll be able to better understand the physics of a traction motor. So basically 86/87 were only higher-rated due to their bigger size and more efficient fans? 
 

(slightly off-topic) Trainz is supposedly getting a physics API that you can create plugins for. Depending on what it entails, would it be possible to properly write a program for AC electric physics based on what we know about roarers/Class 83? A bit too late to go just based off the general feeling of how the real thing drives :)  

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20 hours ago, Evertrainz said:

Would anyone happen to know: 

 

1. what horns the Class 83 had (Desilux? westinghouse? hyson airchime?) or if there is a sound recording of one out there anywhere

 

2. what the single white air brake hose cock was for, when built; could someone confirm that this was for when being towed by another loco to charge its own reservoir/apply brakes? Why did some locos have two of these white cocks instead of one?

 

3. (for drivers) how often was the "maximum power" of 4400 hp reached, or on any AC loco in general? Sorry, I don't have a good understanding of AC lines and how that works. Was it when the OLE was supplying more current than usual due to lower traffic? Accounts of Alan Varley recorded 81017 clocking 114mph on one instance in the late 70s. If this is true, then the Class 83 would be the most powerful BR locomotive produced by English Electric by a handy 1100 hp (take that, Deltic bashers ;) )

 

83_R24.jpg

 

 

Your model is fabulous. 

 

FYI I think the AL6 had the same horns as the later class 25 and AM10s (Desilux?). I don't recall the AL1-AL5 having that type of horn sound.

 

Re the earlier discussion about the colour of the cab interior and control desk, a video has appeared on You Tube of a class 90 cab ride from Tamworth to Crewe which shows a good area of the desk - it's a much darker blue than these early locos - looks very impressive though.

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On 15/11/2020 at 17:15, MidlandRed said:

 

Your model is fabulous. 

 

FYI I think the AL6 had the same horns as the later class 25 and AM10s (Desilux?). I don't recall the AL1-AL5 having that type of horn sound.

 

Re the earlier discussion about the colour of the cab interior and control desk, a video has appeared on You Tube of a class 90 cab ride from Tamworth to Crewe which shows a good area of the desk - it's a much darker blue than these early locos - looks very impressive though.

 

Interesting. The AM10s, 24s/early 25s, and later 25s (the funny sounding ones?) all had Desilux. Here was the only horn clip I could find of a 310 on YouTube: https://youtu.be/2HvFftsi3kQ?t=485. I assume mounting location, air pressure, and how tightly the bell was screwed into the horn base all varied the sound alot even within a single class. You can tell D1015's squeaky horn from D1010's flatter horn sound. D821's horn sounds different from D832. 

 

The 86s had Westinghouse horns like fitted to Class 31s, but maybe they were swapped out later on? The Desilux had a reputation for being very loud whereas the Westinghouse were more quiet.

 

Someone kindly sent me photos and audio of a pair of Desilux horns from a roarer. Actually he said that one horn was from an 81, but the second horn was, after cleaning the grime off, marked with 85007. So I assume at least 85s and 81s were originally fitted with Desilux horns. Some 85s later were swapped out (?) with the Westinghouse horns fitted to 86s. If you remember did all the roarer horns sound more-or-less the same? 

 

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Having seen the "new" 81 shown at Harrow & Wealdstone in an exhibition on the Belmont bay platform circa 1966, I can't remember what colour the cab was! Having worked on the AC locos as a secondman in 1974/75 the cab desks were usually grey. Cab ceilings were nicotine yellow as a lot of footplate crew smoked like chimneys in those days.

 

As for handling, all much of a muchness. the driver had to keep an eye on the ammeters and make sure the needles didn't go into the red for more that a few seconds as that could cause the overloads to trip out. He then had to wait for the tap changer to run back to the off position, reset the overloads, then notch up again.

 

What was of more concern was the ride quality. the 81/85/86 as originally built had similar bogie design and were notoriously rough riders, so much so that it was impossible to fill the cup with tea and not spill any! The 82-84 had a better bogie design and were a lot better ride, but other problems with them meant early withdrawal.

 

The fitment of side coil springs improved the ride somewhat.

 

The white pip on the buffer beam was for control air, this would have provided air on a second loco to operate the air brake on that loco if it was being towed dead. That would have been actuated by an air/vacuum valve on the loco so the operation of the vacuum brake valve in the leading loco would apply the air brake on the second loco. The urinal was somewhere in the equipment compartment or the cab door!

 

As for exact colours, there's no such thing. every batch of paint varies. I've tried getting "London Bus Red" from TR Williamson and they list at least 12 shades of it.

 

Edited by roythebus
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On 15/11/2020 at 20:48, Evertrainz said:


Thanks, I’m taking a physics course next semester that details EMF and general circuits so maybe I’ll be able to better understand the physics of a traction motor. So basically 86/87 were only higher-rated due to their bigger size and more efficient fans? 
 

(slightly off-topic) Trainz is supposedly getting a physics API that you can create plugins for. Depending on what it entails, would it be possible to properly write a program for AC electric physics based on what we know about roarers/Class 83? A bit too late to go just based off the general feeling of how the real thing drives :)  

 

All but one of AL1-AL4 were built with mercury arc rectifiers, but these were changed to semi-conductor rectifiers in the early 1970s. These later type of rectifiers had a smaller footprint, and provided a smoother DC output which meant the inductance chokes that improved the DC supply were able to be smaller too. The 86 and 87 were built with semi-conductor rectifiers to start with, and were 2 ft longer and had smaller wheels meaning there was a bit more space to provide higer-rated equipment, and more powerful traction motors could be used, whilst remaining within the CCE's axle load limit. They were alos unencumbered by the 6.25 to 25kV switchgear that the original locos had.

 

I have not seen the details of the physics API in Trainz, but as you now I'm all for increased simulated driving realism, so it might be worth a look. Much of the information needed is in the 1960 Electrification Conference Papers, but this is just for the early locos before modification of course. I did see a remark somewhere that the 'Roarers' put out about 105 decibels, compared to around 80 dB of the later locos. Something to consider for the sould file!

 

Your model does indeed look fabulous - is that AL1, 3 and 5 you haev done now?

 

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On 15/11/2020 at 01:39, Evertrainz said:

Would anyone happen to know: 

 

1. what horns the Class 83 had (Desilux? westinghouse? hyson airchime?) or if there is a sound recording of one out there anywhere

 

2. what the single white air brake hose cock was for, when built; could someone confirm that this was for when being towed by another loco to charge its own reservoir/apply brakes? Why did some locos have two of these white cocks instead of one?

 

3. (for drivers) how often was the "maximum power" of 4400 hp reached, or on any AC loco in general? Sorry, I don't have a good understanding of AC lines and how that works. Was it when the OLE was supplying more current than usual due to lower traffic? Accounts of Alan Varley recorded 81017 clocking 114mph on one instance in the late 70s. If this is true, then the Class 83 would be the most powerful BR locomotive produced by English Electric by a handy 1100 hp (take that, Deltic bashers ;) )

 

83_R24.jpg

 

Re max power in electrics, its best to think of the throttle being different in diesels and electrics. In diesels it controls supply (ie revs from the engine block) and in electrics it controls demand from the OHLE/3rd rail which is at full power all the time - unless there are lots of trains drawing current at the same time, or the system has become relatively underpowered with age (I model the Milwaukee Road 3000v DC electrification in the Pacific Northwest of the US; it was designed in 1915  for 3000hp boxcab sets and barely coped with pairs 5100hp Little Joes of 1948 vintage). 

 

Horsepower converts to watts; 1000hp approx= 750 kilowatts. 1 watt= 1 amp x 1 volt. When the throttle is advanced on electrics of any type it's increasing the voltage available to the motors, in the case of 81-87 as typically 38 notches as taps off one side of the transformer or other (high on the 82,6,7, low the rest). The motors then draw enough current for their speed to match load conditions and balance when the back EMF voltage meets that supplied. The voltage supplied is fixed for each tap but the amps the motors draw in order to catch up (when accelerating) are not. The greater further and faster the throttle is advanced, the more catching up there is to do, the greater the current draw.  The ammeters on the electrics were colour shaded to make life easier for drivers not having to remember specific numbers that would vary between classes. Irrespective of the notch, the green band indicated what amperage could be maintained indefinitely without overheating (and the top of the green band and at  maximum volts= the continuous rating) . The yellow band was permitted to be used when accelerating, but did involve some overheating which could be tolerated for variable amounts of time- the greater the load the shorter the time. Hour ratings are commonly quoted but 5 and 10 minute ratings for even higher powers would exist, whether or not the numbers are available for reference. These would be in the red zone of the ammeter.

To create a maximum power situation, you'd need a maximum voltage and maximum amps; think of a heavy train or on a gradient with a clear road ahead and then notching up the power rapidly. The amps would build rapidly but peak power demand would occur if notch 38 (max voltage) is reached and maximum amps are being drawn. When the train speed balances and stops accelerating the amps should then settle back into the green zone. If the ammeter remains in the yellow zone, the driver ought to notch back unless there's a mitigating reason, eg making up for delays or cresting a gradient. So a full power scenario is a bit of a freak, while exceeding the continuous rating -ie use of the yellow ammeter band- would be a routine occurrence with gradients and during acceleration. As a very rough rule of thumb the the maximum output of the AC electics was about 50% above the continuous rating; 7800hp for the 87s rings a bell.

 

FWIW the horsepower curve of a class 71 peaks at something like 4000hp, against a continuous rating of only 2500hp, compared with a Deltic at 3300hp at the driveshaft. It' illustrated in OS Nocks Locos of the 20th century vol 3. So while the 83 has the least continuous horsepower of the AC electrics and less than a Deltic, it would easily thrash a Deltic in a drag race thanks to the extra power the 83 could draw. A 71 probably would too.  Not that that ever happened.

Cheers, Neill Horton

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10 hours ago, Anadin Dogwalker said:

The motors then draw enough current for their speed to match load conditions and balance when the back EMF voltage meets that supplied

 

Thanks for that very detailed (and physic-al :) ) explanation, the general idea of electricity/circuitry formulas are new to me. 

 

So basically the only limiting factor for a DC motor in general is the back EMF and the amount of current that can be drawn without overheating? And overheating/overload is only a problem at lower motor rpm. Whereas at higher speeds, the motor is limited by the amount of voltage supplied due to an increasing back EMF?

 

As I understand from everyone's helpful descriptions here, the current is what generates heat (due to exchange of energy) that requires deafening cooling equipment :) .

I think I have a baseline understanding of it now, hopefully. Traction motors want to increase their rpm for the volts supplied (until in equilibrium with back EMF?) so will draw the appropriate amount of current/amps to get to that rpm for the given load. But the amount of current that can be drawn is limited by the cooling equipment. And this is why jumping right into the red ammeter zone causes issues? Too much current/heat required to get the motor spinning at the speed warranted by the voltage?

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13 hours ago, stovepipe said:

 

I have not seen the details of the physics API in Trainz, but as you now I'm all for increased simulated driving realism, so it might be worth a look. Much of the information needed is in the 1960 Electrification Conference Papers, but this is just for the early locos before modification of course. I did see a remark somewhere that the 'Roarers' put out about 105 decibels, compared to around 80 dB of the later locos. Something to consider for the sould file!

 

Your model does indeed look fabulous - is that AL1, 3 and 5 you haev done now?

 

 

I have "done" the AL5, but to a really low standard in comparison. AL1 has paused progress since I want to get the AL3 at least to a level where I can "plug and chug" into any simulator (i.e. get the mesh and textures, LODs, just tangible stuff done). Out of all my project I'm most happy with this one. I'll have to look into routes that these would run on, neither simulator seems suitable for that.

 

The physics API sounds promising but promise must be taken with grain of salt. Someone on the forums claimed to completely bypass the default physics and script a simulation ground-up, using Train.SetVelocity(). He expressed interest in TNI physics, in response to which T Hilliam responded with interest, stating "We're soon to release a full TNI Physics API where users will be able to hook into most of the train physics and create custom plugins. Plugins are written in C++ rather than script."

 

Given what we know about the early roarers in the 1960 Electrification Conference, would it be possible to program in the constraints that have been mentioned here? I know the existing default ammeter is out-of-whack, and many European creators have scripted their own based on complex electric formulas. Specifically, I would like there to be a shut-down, run-down, and reset if the ammeter is pushed into red for too long. Neil above mentions being able to go into red for very brief periods of time; I assume to determine whether a shutdown is necessary, it is required to simulate the heat increase of the motors, and take into account the cooling capacity of the fans? Probably not outlined in the E.C., but I do know they were a number of 1500 rpm cooling fans. 

 

It might be difficult without scripting the altering the OLE voltage in real time (something that I would really love to see) and sending that data to any electric loco that is on that stretch of catenary, but one thing that would be neat is simulating conditions where the locomotive is able to reach its short-term max horsepower. 

 

One last "gimmick" would be a simulated transformer explosion and fire if the reverser is put into the opposite direction when moving at a decent speed in one direction, effectively turning the TMs into generators. Happened to an 81 with a novice driver I believe.  

Edited by Evertrainz
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Perhaps you are being too harsh on yourself - the standards you have reached already surpass what many would be happy with I'm sure. But I can understand it, I have many proto routes that I haven't released because they aren't 'finished enough'. I guess the LMR South route by glen1974 might be the best bet for an early WCML route.

 

It sounds like it may be possible to do most of the characteristics of the loco in the API. I think it may be more interesting to model the neutral section behaviour before line voltage fluctuations - which would not vary greatly normally and the timetable would be cast to mitigate having too many trains in the section.

 

I found this little video of a mercury arc rectifier from a loco - you can see why a fire might have occured on a poor riding roarer, and why they were changed out for a semi-conductor! There were usually one per traction motor, but one AL design, I forget which, had two larger rectifiers powering two TMs each.

 

 

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It's all very well but what you are forgetting are things like train weight, gradient and rail conditions.

 

I remember as a secondman being let loose on an 87 with a 1300 tonne freightliner from Wembley one wet November evening in 1975. It was around the end of the evening peak and we were surprised at being put fast line. I had problems getting the loa moving with the wet rail and we came to a stand near Carpenders Park, the driver got on the phone to advise the box of the problem. I managed to get us moving again and crept through Watford Junction. The driver told me that once we're in Watford tunnel, open it up, use the dry rail in the tunnel to get a decent speed. all very well until we went under the first ventilation shaft. Whizz, bang, wheelslip and the overloads tripped. 

By the time I'd reset we were down to 20 again and leaving the tunnel It was only when we got over the top at Tring that we could get any speed.

 

I hate to think how many expresses had been held up by this episode.

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12 hours ago, Evertrainz said:

 

Thanks for that very detailed (and physic-al :) ) explanation, the general idea of electricity/circuitry formulas are new to me. 

 

So basically the only limiting factor for a DC motor in general is the back EMF and the amount of current that can be drawn without overheating? And overheating/overload is only a problem at lower motor rpm. Whereas at higher speeds, the motor is limited by the amount of voltage supplied due to an increasing back EMF?

 

As I understand from everyone's helpful descriptions here, the current is what generates heat (due to exchange of energy) that requires deafening cooling equipment :) .

I think I have a baseline understanding of it now, hopefully. Traction motors want to increase their rpm for the volts supplied (until in equilibrium with back EMF?) so will draw the appropriate amount of current/amps to get to that rpm for the given load. But the amount of current that can be drawn is limited by the cooling equipment. And this is why jumping right into the red ammeter zone causes issues? Too much current/heat required to get the motor spinning at the speed warranted by the voltage?

Yep, you've got it. The current draw causes heating. Drivers were not supposed to use the red zone at all, opening the throttle too quickly would cause an overload and would trip breakers but I've no idea what figure they were calibrated to. Overheating can be a problem at any speed, its determined by the current draw not RPM. The back EMF of the motors is what determines the balancing speed for any given notch.

To complicate matters, there's field weakening options. Reducing the voltage across the field coils (the electromagnet part) of the motor, while maintaining full voltage to the armature (the spinning part) cuts the back EMF in direct proportion to the voltage cut. (ie a 10% cut gives 10% more speed). This then allows the motor to turn even faster. In orthodox DC machines like the Woodhead electrics (but not the 70/71/74 boosters- they're something else entirely), the use of multiple weak field diverts or resistors gave many extra running notches for any given motor configurations (series, series-parallel, parallel). Most of their throttle notches were resistance notches what were meant to be transited and not used for more than seconds.  In the AC electrics every notch was a running notch, but the use of weak field varied between classes. The highest notches engaged weak field on some, the 86s didn't have any at all to keep the circuits as simple as possible, while the 87 had a permanent 15% (ish) field divert across all the notches to optimise high speed work.

Roys scenario is a bit different, a mix of a heavy train and the loco unable to get a grip on the railhead. And wheelslip condtions and what they do electrically deserve a separate post:^D

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Not so much a prototype question. But how do we feel about this? :D

(note that this isn't electric blue per se - rather my take on what "chromatic blue" looked similar to) 

 

As much as I love electric blue (best BR livery IMO), I do wish they did a little more with the detailing. Perhaps some stripes and whiskers!

 

 

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