S stock query

[swt_passenger]

An 8 car S stock train is through gangwayed throughout, so does anyone know why each set has two different serial numbers, eg 21045/21046 (as pictured in this week's Railway Herald)?

Presumably the two 'half units' cannot be used independently?

 

[jopsuk]

Can't be used independetly, but can be split more easily at the middle and used with a different half-unit (think Eurostars)

 

[Dstock7080]

Can't be used independetly, but can be split more easily at the middle and used with a different half-unit (think Eurostars)

Regrettfully this is not the case, the trains are semi-permanently coulpled into 7 (S7) or 8-cars (S8). The coupling between each 'car' is the same. They are designed to remain together for their lifetime, although 2 have already swapped cars.

 

[jopsuk]

OK, that makes the original question more relevant- why DO they have two numbers?

 

[tom1649]

OK, that makes the original question more relevant- why DO they have two numbers?

Probably just the tradition. LU has never had unit numbers unlike BR, only individual car numbers. They still need a different number for each car for fault reporting etc don't they even if they are in a fixed formation?

An S8 for example will have eight numbers not two or one. An S7 will have seven numbers.

 

[MCR247]

A 3 car 170 (for example) still has seperate numbers for each car, but will still be numbered 170 101, formed of 50101, 55101 and 79101. Why don't LU just do that?

 

[tom1649]

A 3 car 170 (for example) still has seperate numbers for each car, but will still be numbered 170 101, formed of 50101, 55101 and 79101. Why don't LU just do that?

Probably because they don't use TOPS, so unit numbers aren't important. They have stuck with the current numbering system presumably to be consistent.

 

[causton]

Indeed, in the mind of LU, why have 4 numbers when you can just have three (in that example)? Obviously on the mainline there's a bit more reasoning...

 

[Peter Mugridge]

For convenience ( and to save paper! ) I treat the Underground's units as exactly that - units! Even though they are not formally treated as having unit numbers I just identify them by the number of the least confusing vehicle in each one, thus:

A Stock: The even numbered 5xxx vehicle.
C Stock: The 5xxx vehicle.
D Stock: The 17xxx vehicle ( due to there being a few double enders ).
S Stock: The 21xxx vehicle at each end.

1972 Stock: The 32xx and 34xx vehicles.
1973 Stock: The centre vehicle ( same reason as D Stock ).
1992 Stock: The 92xxx vehicle.
1995 Stock: The 51xxx vehicle.
1996 Stock: The 96xxx vehicle.
2009 Stock: The 11xxx vehicle.

 

[12CSVT]

Quite a lot of EMUs in British Rail ownership never had unit numbers until the late 1980s - Euston to Watford class 501s, Merseyrail class 502s and 503s (withdrawn by early 1980s without ever having unit numbers), Bury line class 504s, Hadfield line class 506s (withdrawn by 1984). Same goes for many first generation DMUs.

 

[Dstock7080]

Probably because they don't use TOPS, so unit numbers aren't important.

I understood that C & D Stock are allocated TOPS numbers for NR Operating purposes? Also, DR trains are given NR reporting numbers when on NR metals- ie. 2E73 (Edgware Rd, train 073).

For convenience ( and to save paper! ) I treat the Underground's units as exactly that - units! Even though they are not formally treated as having unit numbers I just identify them by the number of the least confusing vehicle in each one, thus:

S Stock: The 21xxx vehicle at each end.

Why both numbers? One number is sufficient to find the whole formation (as with '09 Stock).

 

[tom1649]

I understood that C & D Stock are allocated TOPS numbers for NR Operating purposes? Also, DR trains are given NR reporting numbers when on NR metals- ie. 2E73 (Edgware Rd, train 073).

I have a vague memory of this being mentioned before. I think LUL stock is Class 499 followed by a subclass depending on the type of stock. Would the 1972 stock need TOPS numbers for operating north of Queen's Park on the Bakerloo then?

I've always identified LUL units by the leading DM (Driving Motor). But as Peter rightly says, there are some double ended units which may confuse matters.

 

[Peter Mugridge]

Why both numbers? One number is sufficient to find the whole formation (as with '09 Stock).

Because I don't trust them not to split and re-match the units even though they say they never will....

 

[DavyCrocket]

Also, DR trains are given NR reporting numbers when on NR metals- ie. 2E73 (Edgware Rd, train 073).

Why both numbers? One number is sufficient to find the whole formation (as with '09 Stock).

The numbers are what they think the train is though!
Having dealt with a signal failure, it got in a right mess, as they went on what their visual was saying rather than the actual train set number.
Their data/visual that gives the reporting code is generated by an LU Programme Machine and can be edited - if it's working or done in time!

 

[bb21]

The two halves of an S-stock train aren't numbered in the same way though. An example being:

21011+22011+23011+24011+24012+25012+22012+21012

Don't they need two sets of numbers because three of the carriages are duplicates of three of the other ones? The third carriage from the front having, presumably, a different specification to the third carriage from the back. If identical carriages are numbered in the same range then surely it is easier to identify them when the need arises to swap them or move an odd carriage somewhere else. I know they say that they won't be swapped but it is always a possibility somewhere down the line, due to, maybe, accidents, etc.

 

[WinterChief]

S Stock cars have been swapped already.

the 25xxx number, is a de-icer.

 

[bb21]

S Stock cars have been swapped already.

the 25xxx number, is a de-icer.

Renumbered afterwards?

 

[Dstock7080]

Renumbered afterwards?

Yes, soon after they left from Derby.

 

[Dstock7080]

The two halves of an S-stock train aren't numbered in the same way though. An example being:
21011+22011+23011+24011+24012+25012+22012+21012

The first production non-deicer has now arrived (excepting 099/100):
21057-22057-23057-24057-24058-23058-22058-21058.
The 2nd number indicating the type of car, DM, M1, M2 or MS.

Testing of S7s between Barking and Aldgate East was occurring today too