Would standardised rolling stock make any sense these days?

jopsuk · 31 Aug 2019

Swanny200 said:
Wasn't the original "Networker" plan supposed to cover all 3 NSE sectors until it was decided that it would only cover the Kent lines and KX?

Absolutely, with time & funding that was very much the plan- even the 319s would have been either replaced by or worked alongside the Class 371.

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krus_aragon · 31 Aug 2019

The Ham said:
Given that your can run a lot of data (1,000mb/s) over a standard network cable, it should be fairly easy to have it that you have a standard connection which allowed the transfer of data between units using a similar system. Yes you'd need a pin for each wire within the cable, but it shouldn't be too hard to have 8 pins.

Yes, it'd be possible to modulate several different signals onto a small number of wires. Older multiple working systems would have used separate wires for every control signal as embedded computer systems weren't available/affordable/reliable enough at the time. There may be some situations where dedicated wires for a single purpose (such as a brake control wire) may still be desirable.

When you consider where we're headed with ERTMS, an on-board packet-based communication system (or something of that ilk) doesn't sound that unusual.

AM9 · 1 Sep 2019

The Ham said:
Given that your can run a lot of data (1,000mb/s) over a standard network cable, it should be fairly easy to have it that you have a standard connection which allowed the transfer of data between units using a similar system. Yes you'd need a pin for each wire within the cable, but it shouldn't be too hard to have 8 pins.

Now you'd want to ensure that you could be sure that the connection was made every time, so you may want 16, 24 or 32 depending on how much redundancy you want to allow for or if you wish to have a set for non critical data transfer. However as it would be using multiple cables you could have the system just use the first 8 available wires.

You then just need a box in each unit to convert between the control inputs and the data transfer.

Given that such boxes are small and fairly cheap for going from VGA or HDMI to cat 5/6 and then back again, likewise most digital sound desks use cat 5/6 cables with a stage box at the other end, I'm sure you could develop a box which allowed any train to talk to any other with regards to applying power, breaking, announcements, etc. If the system was smart enough you could even have it so that a slower unit told a faster unit that it couldn't go faster if asked to do so.

You may wish to develop a protocol to ensure that emergency systems (such as full breaking) had priority over any other data being transferred.

Given that no one will be wanting lightning quick reactions (we're not playing a first person shooter game) a lag of a few m/s to convert, transfer and convert back shouldn't cause problems.

Bandwidth of modern digital interfaces would not be a constraint on the amount of data involved in complete control. What would be an issue is the durability of such an interface:

a) it's physical durability to operate in the less than clinical conditions of autocouplers
b) it's ability to operate reliably with some or all of the associated terminal devices under out-of-specification supplies
c) it's ability to operate reliably under quite extreme electromagnetic interference (EMI) conditions and not to suffer electrical failures

Given that any electronic equipment may fail, there would be a need for certain high priority signals to be communicated by hard-wired descrete signals, e.g. braking, power and temperature overload monitoring, especially of equipment directly concerned with the operation of multiplexed buses.

The Ham · 2 Sep 2019

AM9 said:
Bandwidth of modern digital interfaces would not be a constraint on the amount of data involved in complete control. What would be an issue is the durability of such an interface:

a) it's physical durability to operate in the less than clinical conditions of autocouplers
b) it's ability to operate reliably with some or all of the associated terminal devices under out-of-specification supplies
c) it's ability to operate reliably under quite extreme electromagnetic interference (EMI) conditions and not to suffer electrical failures
Given that any electronic equipment may fail, there would be a need for certain high priority signals to be communicated by hard-wired descrete signals, e.g. braking, power and temperature overload monitoring, especially of equipment directly concerned with the operation of multiplexed buses.

Clearly you wouldn't be relying on a RJ45 plug/socket rather a more robust system. As long as you can make a reliable contact then it would work. As I suggested in my post, you had multiple wires which could be used even though not all of them would be so as to have reduncy.

The communication boxes would be able to test the integrity of each connection route in time so that if one pin wiggled and lost its connection the data would be rerouted.

If you wanted further reduncy you could have a Bluetooth (or other short distance communication system) connection which could an all stop if the hard data connection was compromised and was unrecoverable.

In fact it could be argue that such a system could be more reliable as you're not relying on a single dedicated communication route.

hwl · 2 Sep 2019

The Ham said:
Clearly you wouldn't be relying on a RJ45 plug/socket rather a more robust system. As long as you can make a reliable contact then it would work. As I suggested in my post, you had multiple wires which could be used even though not all of them would be so as to have reduncy.

The communication boxes would be able to test the integrity of each connection route in time so that if one pin wiggled and lost its connection the data would be rerouted.

If you wanted further reduncy you could have a Bluetooth (or other short distance communication system) connection which could an all stop if the hard data connection was compromised and was unrecoverable.

In fact it could be argue that such a system could be more reliable as you're not relying on a single dedicated communication route.

Bombardier et al have been running network connections through Dellner Autocouplers for quite a while now (379s onwards) and making all the equipment modules network addressable as this significantly reduces the wiring required. The max data rates aren't great due to impedance changes from cat5/6 but as has already been pointed out you don't need high data rates.

krus_aragon · 2 Sep 2019

The Ham said:
Clearly you wouldn't be relying on a RJ45 plug/socket rather a more robust system. As long as you can make a reliable contact then it would work. As I suggested in my post, you had multiple wires which could be used even though not all of them would be so as to have reduncy.

The communication boxes would be able to test the integrity of each connection route in time so that if one pin wiggled and lost its connection the data would be rerouted.

If you wanted further reduncy you could have a Bluetooth (or other short distance communication system) connection which could an all stop if the hard data connection was compromised and was unrecoverable.

In fact it could be argue that such a system could be more reliable as you're not relying on a single dedicated communication route.

There would also be the need to prove to the RSSB (or relevant bodies) that this novel approach is reliable, which would take some time.

What we really need is a central body that believes strongly enough in this approach to spend the time and effort to get it done.

hwl · 2 Sep 2019

krus_aragon said:
There would also be the need to prove to the RSSB (or relevant bodies) that this novel approach is reliable, which would take some time.

What we really need is a central body that believes strongly enough in this approach to spend the time and effort to get it done.

The later electrostars and Aventras (ex 345 as no coupling in service) already have have a mixed analogue and networked connection autocoupler approach, the core safety critical stuff remains analogue. The pin outs are already in the RSSB coupling standards document.

krus_aragon · 2 Sep 2019

hwl said:
The later electrostars and Aventras (ex 345 as no coupling in service) already have have a mixed analogue and networked connection autocoupler approach, the core safety critical stuff remains analogue. The pin outs are already in the RSSB coupling standards document.

There we go, then.

On to the step of using that precedent to make a universally compatible connector (with suitable software APIs too)...

AM9 · 2 Sep 2019

The Ham said:
Clearly you wouldn't be relying on a RJ45 plug/socket rather a more robust system. As long as you can make a reliable contact then it would work. As I suggested in my post, you had multiple wires which could be used even though not all of them would be so as to have reduncy.

The communication boxes would be able to test the integrity of each connection route in time so that if one pin wiggled and lost its connection the data would be rerouted.

If you wanted further reduncy you could have a Bluetooth (or other short distance communication system) connection which could an all stop if the hard data connection was compromised and was unrecoverable.

In fact it could be argue that such a system could be more reliable as you're not relying on a single dedicated communication route.

The issue is more than the connector. Of course an RJ45 would be totally inappropriate. There are plenty of high perfromance interface systems that can be used there, especially from the military component world. The big risk is maintaining adequate EMC performance in the presence of a quite agressive EMI environment. The compliance of the power electronic systems on board are designed with current conventional interfaces in mind. With fairly extensive use of discretes for critical signals and controls multiplexed buses can provide some economy of inerconnects for low priority data, where multiple data collisions on a CDMA link can be tolerated. If critical services depend on such an interface, there could at best be considerable slowing down of some capabilities. At worse, that could lead to significant safety issues.

AY1975 · 2 Sep 2019

Mikey C said:
The Southern Region was very standardised. Which had great benefits I presume for maintenance and reliability, but did lead to a lack of design progression and slam door Mk1 based units like the Class 423 still being made in 1974, using the same traction motors that had first been used 30/40 years earlier!

Indeed! I suppose you could say the CIG/BIG was a development of the CEP/BEP (which could be described as a development of the 4-COR), but the CEPs/BEPs were mostly built in the mid to late 1950s, yet they were still building CIGs/BIGs into the early 1970s.

See also the thread on why slam-door trains continued to be built for so long after sliding door technology had been developed at https://www.railforums.co.uk/threads/why-were-slam-door-trains-still-built-so-late-on.172064/

Sleeperwaking · 2 Sep 2019

a_c_skinner said:
Mk3 and Mk4 are (wiki here) 23m. They seem widely cleared to run so it doesn't seem to me to be beyond the wit of humankind to only buy new stock that is the right size to run everywhere and have the same sort of couplings and brake hoses at each end. It isn't anticompetetive, you just specify the same for everyone. Even the Carlisle and Maryport can take some 23m vehicles so it cannot be too difficult to clear the vast bulk of the network for a useful "go anywhere" passenger vehicle size. Add in a standard driving cab and door controls. As above the problem is it needs someone to take control but the gains in being able to move stock around, reduced training, rescuing stranded vehicles must be substantial.

However, Mk3 / Mk4 coaches have end doors. You get much more overthrow from a double door width passenger footstep at a 1/3 2/3 door position than from a single door width footstep much closer to the bogie. They also didn't have to comply with the latest step position requirements, which are specified relative to a standard platform height / offset that hardly any UK platforms conform to as they were generally built decades before the standard came into being. Also, gauging methodology has completely changed since the Mk3s/4s were introduced - chances are that if they were analysed again using modern gauge analysis software, they would come up as being foul against structures on routes they're currently cleared over.

hwl · 2 Sep 2019

AM9 said:
The issue is more than the connector. Of course an RJ45 would be totally inappropriate. There are plenty of high perfromance interface systems that can be used there, especially from the military component world. The big risk is maintaining adequate EMC performance in the presence of a quite agressive EMI environment. The compliance of the power electronic systems on board are designed with current conventional interfaces in mind. With fairly extensive use of discretes for critical signals and controls multiplexed buses can provide some economy of inerconnects for low priority data, where multiple data collisions on a CDMA link can be tolerated. If critical services depend on such an interface, there could at best be considerable slowing down of some capabilities. At worse, that could lead to significant safety issues.

Already done through the newest iterations of the the standard Dellner auto coupler connections with sprung pin and contact (all gold plated)

Some detail in the Dellner Brochure:
https://www.dellner.com/Downloads/Brochure_English.pdf
Ethernet capability first introduced in 2007.

a_c_skinner · 2 Sep 2019

Sleeperwaking said:
However, Mk3 / Mk4 coaches have...

I am sure you are right, but that doesn't detract from the idea that in principle modest sacrifices and modest work would allow us to have all our rolling stock capable of being redeployed all over the network and all of them coupled to each other to allow movement at least. We are currently in the foolish position of ordering basically class 802 stock with a different body length for the MML because we've not set interoperability as a goal. It would have taken some time but structures on the MML don't seem so radically different to GW & ECML as to preclude having got to interoperability by now.

AM9 · 2 Sep 2019

hwl said:
Already done through the newest iterations of the the standard Dellner auto coupler connections with sprung pin and contact (all gold plated)

Some detail in the Dellner Brochure:
https://www.dellner.com/Downloads/Brochure_English.pdf
Ethernet capability first introduced in 2007.

Their D-REX data connection looks similar to robust test panel connectors inserts (e.g. Mac-Panel or Virginia Panel). That's the easypart. Getting consistent, reliable and through-life system EM immunity in the environment could delay safety critical multiplexed signal connections being accepted for service use, which is presumably why there are so many discretes on the pin-face.

JamesT · 2 Sep 2019

AM9 said:
Their D-REX data connection looks similar to robust test panel connectors inserts (e.g. Mac-Panel or Virginia Panel). That's the easypart. Getting consistent, reliable and through-life system EM immunity in the environment could delay safety critical multiplexed signal connections being accepted for service use, which is presumably why there are so many discretes on the pin-face.

https://www.railengineer.co.uk/2016...ey-links-in-new-generation-on-train-networks/ is somewhat of an advert, but they are claiming they can manage EMI immunity with shielded cabling. Different company, but the principles will be the same.

Would standardised rolling stock make any sense these days?

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