Why do 153s need Unit and Vehicle Numbers?

[TheEdge]

The title is fairly self explanatory. Surely with a 1 vehicle train they are one and the same.

 

[gage75]

IIRC it's because they were originaly two car 156 units that were split to make single car 153 units
Although if someone else knows better I'm happy to be corrected

 

[HSTfan!!!]

Do the vehicle numbers originate from when they were part of the 155's?

 

[IanXC]

Don't the 121s and 139s also have vehicle numbers in addition to unit numbers too?

 

[Eagle]

Vehicle numbers and unit numbers have different formats (vehicles are 5-digit, units are 6-digit), so it would need both otherwise it'd probably mess up some system somewhere.

 

[Cherry_Picker]

It's probably more effort to create a completely new system for single car trains than it would be just to keep them within what already exists.

 

[PHILIPE]

Of course they've to have a Unit number to identify them. All vehicles should have it's own number as well for things such as maintenance.

 

[hairyhandedfool]

Do the vehicle numbers originate from when they were part of the 155's?

Sort of.

153301-153335 had coach numbers 52301-52335 when part of the 155s and they still have these numbers.

153351-153385 had coach numbers 57301-57335 when in the 155s but are now 57351-57385.

 

[12CSVT]

The Parry People Movers on the Stourbridge branch have coach numbers (39001 and 39002) as well as unit numbers (139001 and 139002).

Same with Southern Region class 419 MLVs (unit numbers 90xx and coach numbers 680xx) and class 489 GLVs (unit numbers 91xx and coach numbers 685xx)

 

[jopsuk]

I think the system essentially requires it?

I'd re-write the system so that vehicle numbers were 8-digit. Locos would be 0xxxxx00. MU vehicles would be cccsuuvv where
ccc = class
s = sub class
uu = unit
vv = vehicle

so eg 153301/52301 would become 15330101

Would be a huge programming and data entry project though. However it would eliminate future loco number/unit vehicle number clashes.

 

[455driver]

It aint broke so why fix it?

Every* unit has a coach nuymber and a unit number, they always have even the original 121 and 122s had both sets of numbers.

* I am aware of some that dont but they are outside the scope of this thread.

 

[TheEdge]

Fair enough, I did suspect it probably had something to do with not breaking various systems.

 

[PHILIPE]

IIRC it's because they were originaly two car 156 units that were split to make single car 153 units
Although if someone else knows better I'm happy to be corrected

155s not 156s

 

[met331]

122 units are numbered in the 55xxx series

 

[Xenophon PCDGS]

122 units are numbered in the 55xxx series

Did not the first generation BR Derby Lightweight DMU fleet have two single units...79900 and 79901 ?

 

[gage75]

155s not 156s

Oops my bad

 

[swt_passenger]

I think the system essentially requires it?

I'd re-write the system so that vehicle numbers were 8-digit. Locos would be 0xxxxx00. MU vehicles would be cccsuuvv where
ccc = class
s = sub class
uu = unit
vv = vehicle

so eg 153301/52301 would become 15330101

Would be a huge programming and data entry project though. However it would eliminate future loco number/unit vehicle number clashes.

Just noticed this. How would it work for a sub class of more than 99 units, such as the 450s, which had 127 units as built, 450001-450127.

 

[D6975]

Just noticed this. How would it work for a sub class of more than 99 units, such as the 450s, which had 127 units as built, 450001-450127.

You'd have to bodge it by saying that the 0 and 1 subclasses are the same.
Hardly an elegant solution but it would work.

If you're going to re-write the numbering rule book you might as well go the whole hog and have a system similar to the european wagon system.

So one end vehicle of 450 127 would be something like:

05-450-0-127-01

05 being for arguments sake, the code for a DC emu vehicle,
450 - class,
0 - sub class
127 - unit no
01 - vehicle no

converting the unit to AC or dual voltage would only involve changing the first 2 digits, the rest could remain the same. edit - or poss change the sub class no as well.

 

[HSTEd]

Just noticed this. How would it work for a sub class of more than 99 units, such as the 450s, which had 127 units as built, 450001-450127.

Well it would be no worse off than with the current system, which essentially has a nominal 450/0 and 450/1 subclass being identical.

 

[theblackwatch]

Well it would be no worse off than with the current system, which essentially has a nominal 450/0 and 450/1 subclass being identical.

There is no such 450/1 subclass - just because a unit is numbered as 4501xx does not mean it is a 450/1! Sinllarly, 47854 is a 47/4, not a 47/8, and 26038 is a 26/1.

 

[HSTEd]

There is no such 450/1 subclass - just because a unit is numbered as 4501xx does not mean it is a 450/1! Sinllarly, 47854 is a 47/4, not a 47/8, and 26038 is a 26/1.

If there is no subclass field we loose absolutely nothing by having one that is used almost but not all of the time.

 

[61653 HTAFC]

There aren't really any 'unbreakable' rules when it comes to numbering systems anyway- For example the class 175s have 2 sub-classes: 175/0 being 2-car units and 175/1 being 3-car. The class 144s though, aren't divided into sub-classes between the 2-car (144001-013) and 3-car (144014-023) units. I don't know if Northern are able to separate the units for diagramming purposes nor whether they would choose to do so anyway.

 

[455driver]

There aren't really any 'unbreakable' rules when it comes to numbering systems anyway- For example the class 175s have 2 sub-classes: 175/0 being 2-car units and 175/1 being 3-car. The class 144s though, aren't divided into sub-classes between the 2-car (144001-013) and 3-car (144014-023) units. I don't know if Northern are able to separate the units for diagramming purposes nor whether they would choose to do so anyway.

The 144s were built as 2 coach trains and had the centre car added after a couple of years.