DC only Electrostars

[Prestige15]

Curious to know why DC only Electrostars was never classified as 475-477 unlike the DC only Desiros?

 

[Class465pacer]

According to Wikipedia (no source provided for this claim) 375s, 376s and 377s have space on the roof for pantographs to be fitted at some point in the future.

I also know the first batch of 375s (375/6s) have pantographs.

 

[computerSaysNo]

They were built with a pantograph well on the appropriate carriage, and as far as I'm aware there is space left somewhere in/on/underneath the train for AC equipment to be installed.

 

[py_megapixel]

They were built with a pantograph well on the appropriate carriage, and as far as I'm aware there is space left somewhere in/on/underneath the train for AC equipment to be installed.

Isn't that also the case for the 450s, given that they are in every other way identical to a 350?

 

[Domh245]

Isn't that also the case for the 450s, given that they are in every other way identical to a 350?

The provision on the electrostars is a bit more than that on the desiros AIUI, including things such as the lump of concrete that each DC only electrostar lugs around in lieu of a transformer, and more of the necessary wiring being installed but not connected.

As for why they electrostars were 37x rather than 47x, like @Class465pacer says, the first batch of units ordered were dual-voltage (the 375/6s) - the 3 car 375/3 fleet followed, and despite being nominally DC only they make sense as a variant of 375 than a new fleet (same logic with the latter 375 fleets /7-/9). The conversion to 377 by changing the coupler makes things a bit messy as they could have gone 475 or 477, but AIUI at the same sort of time, the plans for the /1, /4, and critically /2 fleets were also in the works, again logically giving the class a 3xx number. The only real misnomer is the 376, being purely DC only (with AC provision admittedly) but with no basis for a 3xx number at the time. I suppose the logic was to keep the -stars in the same ballpark rather than splitting them into different ranges.

 

[computerSaysNo]

Isn't that also the case for the 450s, given that they are in every other way identical to a 350?

I believe 377s are based on 375s which are based on 357s, which are exclusively AC-powered. This may be why they are numbered in the 3xx range.
I'm not sure what the 450s are based off, if it was a DC design then that could account for them being numbered in the 4xx range.

 

[Philip Phlopp]

The provision on the electrostars is a bit more than that on the desiros AIUI, including things such as the lump of concrete that each DC only electrostar lugs around in lieu of a transformer, and more of the necessary wiring being installed but not connected.

As for why they electrostars were 37x rather than 47x, like @Class465pacer says, the first batch of units ordered were dual-voltage (the 375/6s) - the 3 car 375/3 fleet followed, and despite being nominally DC only they make sense as a variant of 375 than a new fleet (same logic with the latter 375 fleets /7-/9). The conversion to 377 by changing the coupler makes things a bit messy as they could have gone 475 or 477, but AIUI at the same sort of time, the plans for the /1, /4, and critically /2 fleets were also in the works, again logically giving the class a 3xx number. The only real misnomer is the 376, being purely DC only (with AC provision admittedly) but with no basis for a 3xx number at the time. I suppose the logic was to keep the -stars in the same ballpark rather than splitting them into different ranges.

Yes, the ballast is provided in lieu of the transformer so the unit mass remains the same, enabling the suspension settings and track access charges to be the same regardless of whether a unit is dual-voltage or DC only.

 

[Domh245]

I'm not sure what the 450s are based off, if it was a DC design then that could account for them being numbered in the 4xx range.

450s were first/joint first along with the 360s. The fact that none of the order was originally intended as dual voltage explains why they were registered as pure DC EMUs. Later when the SRA turned 120 vehicles of the order into dual voltage units for Silverlink/Central, they had to be introduced as a new class

 

[jopsuk]

Just because there's supposed to be some sort of logic in the TOPS numbering doesn't mean that it is followed consistently. Often it's what the manufacturer or lead operator asked for because they thought it seemed a good number.

Hell, the Electrostar line is a good example of that. You've got Class 357 being followed by 375, but the 377s were ordered at about the the same time and given a different class number purely to denote the different coupler; a distinction that went soon after but they remained as separate classes. Class 376 is a variant of the family, inserted awkwardly between the other two DC classes. Class 378 is then a development of the 376. 379s are an AC-only version, and then 387s were very nearly just class 377/8 until as far as I understand it was decided that the systems on board and software versions were too far advanced to be made compatible with the rest of the 377 fleet.

 

[jopsuk]

Of course under BR the Southern region had a systematic numbering scheme, not replicated outside of the area. The last units to follow it were the Networkers* , the Desiros and Junipers despite being 4xx don't fit. It would have needed a re-use of the middle digit, with some decision made as to how to differentiate a four car Juniper, Desiro (or indeed Electrostar) given they would all have counted as "four car outer suburban" and been 4x3. I guess wrapping around to 0 and allocating based on product line (rather than on decade) would have worked. Alternatively the rolling stock library could have reached for 6xx, 7xx, 8xx ranges immediately at post privatisation and gone a different route entirely

 

[Domh245]

You've got Class 357 being followed by 375, but the 377s were ordered at about the the same time and given a different class number purely to denote the different coupler;

Point of order - 375s were first ordered by Connex in August 1997, the main 377 orders came under Govia in 2001 and 2002 - a 4 year gap isn't really "the same time" IMO! Similarly, the 'different coupler' was true of the time, but also reflected the different operator, something that has continued to happen since privatisation (and indeed happened pre-privatisation too with things like the 158s v 159s)

 

[61653 HTAFC]

Point of order - 375s were first ordered by Connex in August 1997, the main 377 orders came under Govia in 2001 and 2002 - a 4 year gap isn't really "the same time" IMO! Similarly, the 'different coupler' was true of the time, but also reflected the different operator, something that has continued to happen since privatisation (and indeed happened pre-privatisation too with things like the 158s v 159s)

I'd always understood it that the initial order for South Central was done under Connex (before they were booted out) and that those units were initially also set to be 375s... With GoVia amending the order and reclassifying once they took over before any of the units had been delivered. But as we know, the human memory isn't the most reliable!

There were a few other things besides operating sector to differentiate between 158s and 159s. The original WoE units were all 400hp variants and had controlled emission toilets from new (or rather had them added at Rosyth prior to entering service). They also had 1st class from new, which the RR 3-car units only gained after Northern Spirit took over.

 

[RichardKing]

I'd always understood it that the initial order for South Central was done under Connex (before they were booted out) and that those units were initially also set to be 375s... With GoVia amending the order and reclassifying once they took over before any of the units had been delivered. But as we know, the human memory isn't the most reliable!

I believe this is why 377s 101-139 had the Southeastern interior prior to the 2012 (I think) refresh.

 

[Prestige15]

I believe 377s are based on 375s which are based on 357s, which are exclusively AC-powered. This may be why they are numbered in the 3xx range.
I'm not sure what the 450s are based off, if it was a DC design then that could account for them being numbered in the 4xx range.

I'm pretty sure the 450 were based on a exclusively AC-powered unit, Class 360