Class 91/IC225 Driving Technique

[Kurolus Rex]

Hi there!

I've recently taken an interest in the IC225 sets as of late and was interested in learning about the various driving techniques used when departing stations.

To be clear here, i'm not trying to find a technique that all drivers use, that works in all conditions etc. These techniques will of course vary from driver to driver, be affected by signal aspects, gradients, rail adhesion and perhaps a dozen other factors too.

I'm looking for information on things such as the following:

-When brakes are released
-How much power is applied from a stand still
-How quickly power is increased; are there any vague patterns?
-When the reverser is moved into the direction of travel

Any insight into this topic would be greatly appreciated!

 

[tellytype]

Not a driver, although I've driven the 91 Desk at GNER/VTEC/LNER.

Brakes are released when you want to go. Obviously.
You need the handle in the direction of travel before you take power.
You take notch 1 from a standstill from what I can remember, although that will depend on the gradient on departure - these are awesomely powerful machines & notch 1 will power you up most stuff.

Once you reach an unrestricted section of line you can open up but it doesn't take long to get to line speed so you'll very quickly hit the limiter (which you can set) or need to manage the power/brake to keep under the max.

I seem to recall that there is something special about taking power quickly again after a neutral section, that causes the system to lose the plot & NOT apply the power you've asked for so you have to pull the power back to zero & ask again.

I'm sure someone who knows MUCH more than me will be along in a minute to tell you how it SHOULD be done & not my badly remembered version

 

[73001]

It would be interesting to know if there is much difference between the loco end and the DVT end when it comes to driving too. Which do drivers prefer and why?

 

[Darandio]

There is actually a very interesting official East Coast document available online. https://www.whatdotheyknow.com/requ.../3/East Coast Professional Driving Policy.pdf

This bit is of interest to the questions asked:

1. Use of the power controller Start the train using a low power setting, (notch 2 or 3) taking gradients into account and allow the train to reach 3 to 5 mph before moving the power controller to a higher setting.

 

[tellytype]

Notch 2...thats the one. See, thats why I'm not a driver, pants memory!

I dont think the loco & DVT are any different in terms of whats in the driving cab.

 

[Kurolus Rex]

Not a driver, although I've driven the 91 Desk at GNER/VTEC/LNER.

Brakes are released when you want to go. Obviously.
You need the handle in the direction of travel before you take power.
You take notch 1 from a standstill from what I can remember, although that will depend on the gradient on departure - these are awesomely powerful machines & notch 1 will power you up most stuff.

Once you reach an unrestricted section of line you can open up but it doesn't take long to get to line speed so you'll very quickly hit the limiter (which you can set) or need to manage the power/brake to keep under the max.

I seem to recall that there is something special about taking power quickly again after a neutral section, that causes the system to lose the plot & NOT apply the power you've asked for so you have to pull the power back to zero & ask again.

I'm sure someone who knows MUCH more than me will be along in a minute to tell you how it SHOULD be done & not my badly remembered version

Class 91s still have Notches? I've seen the older 10 Notch power handle before but i was under the impression that this was replaced with a 'Notchless' power handle more recently. I've heard people claim that drivers keep the brakes on initially, apply power and then release to give a smoother pull away, hence why i was asking about the brakes. Are you aware of any such techniques?

There is actually a very interesting official East Coast document available online. https://www.whatdotheyknow.com/request/250488/response/620584/attach/3/East Coast Professional Driving Policy.pdf

This bit is of interest to the questions asked:

Thanks, i'll have a read!

 

[73001]

I dont think the loco & DVT are any different in terms of whats in the driving cab.

... I meant more in terms of technique when pushing or pulling the train.

 

[EE Andy b1]

It would be interesting to know if there is much difference between the loco end and the DVT end when it comes to driving too. Which do drivers prefer and why?

Not drove Class 91s, but have drove Class 90s and Class 87s with the Mk3 DVT (Driving Van Trailer).

Much prefer driving from the locomotive anytime. More enjoyable to my mind and more responsive to controls unlike driving from the DVT which is slightly more sluggish in operation. The feel can be quite different under braking.
With the 87s propelling you also had to get your timing right running the power off for Neutral sections or a bang and a snatch through the train. The same with giving too much power and could overload the 87. Much easier with the 90 (Thyristor Control), 91 the same i should imagine.
Driving from the loco you can see the ammeters and power applying, on the Mk3 DVT we just had a traction light for when power was applied.
On the DVT you only had the train brake so had to hold in initial brake application, then apply power on re-starting from a stop. On the loco you could hold on the straight air brake (level & rising gradient).
You just got used to it with experience. I found the Class 90s to have a lot more wheelslip in wet condition, 91s seem to do the same, anti-slip and auto power reduction to each axle.

 

[pdeaves]

When I had brief involvement with 91s when they were new, most drivers simply put the speed limiter dial to whatever they wanted to do. Possibly low speed was treated differently, I don't remember.

 

[captainbigun]

89, 90 and 91 all have notchless power controllers. The first detent is minimum TE and then you can put the controller wherever you want. It’s not power per se but tractive effort, fully open is maximum demand. The DVTs also have notchless controller with an initial minimum detent. That’s converted into an 8 bit equivalent and sent down the TDM. The exception is the Mk3 DVTs converted for use with 67 or 68 which do have notches, though when used via TDM the same applies as when notchless.

If you use speed set the. You set the dial at the desired speed and open the controller as desired, the loco’s micro will then use the controller position to dictate the maximum TE to be used in getting to the set speed. Or not if that setting is too low. Equally the micro can use the rheostatic brake on the loco to reduce speed. Though I believe this is no longer the preferred driving method.

I suspect the document reference is a cut and paste error from the equivalent HST document.

90s have ammeters, 91s don’t. Diving technique effectively the same.

The 87s shouldn’t overload when pushing, the demand is controlled based upon the actual current seen in the traction motors (using the highest of the four), more likely poorly setup overloads....which is a tricky job that takes time and patience.

 

[Kneedown]

I've heard people claim that drivers keep the brakes on initially, apply power and then release to give a smoother pull away, hence why i was asking about the brakes. Are you aware of any such techniques?

On any train a Driver will release the brakes only when power has been taken to prevent rollback on an uphill gradient.

 

[Kurolus Rex]

Thanks for the replies!

So, does this mean that 91 drivers will typically start in the first detent of the power controler and then gradually build it up? I've heard before that 91 drivers don't usually use more than about 70% throttle until the train is clear of the platform; is this true or do drivers just build it up to maximum TE without thinking about this?

 

[hexagon789]

There is actually a very interesting official East Coast document available online. https://www.whatdotheyknow.com/request/250488/response/620584/attach/3/East Coast Professional Driving Policy.pdf

This bit is of interest to the questions asked:

What notches are these? 91s are notchless from initial (10% power). Unless they mean the markings of 1 to 10 on the DVT power controller, though that is still notchless and I assume a guide for if they were ever used with older tap changer locos such as 87s because the DVTs lack an ammeter.

Thanks for the replies!

So, does this mean that 91 drivers will typically start in the first detent of the power controler and then gradually build it up? I've heard before that 91 drivers don't usually use more than about 70% throttle until the train is clear of the platform; is this true or do drivers just build it up to maximum TE without thinking about this?

Possibly superceded, but on one video of a 225 leaving King's Cross (15 exit limit), the driver pulled the power controller back halfway, released the brakes and as soon as the train moved pulled the handle fully back.

 

[hexagon789]

There is actually a very interesting official East Coast document available online. https://www.whatdotheyknow.com/request/250488/response/620584/attach/3/East Coast Professional Driving Policy.pdf

This bit is of interest to the questions asked:

Actually I wonder if that's more in reference to HSTs? Notch 2 or 3 would be a typical enough notch to start one moving in.

 

[Kurolus Rex]

What notches are these? 91s are notchless from initial (10% power). Unless they mean the markings of 1 to 10 on the DVT power controller, though that is still notchless and I assume a guide for if they were ever used with older tap changer locos such as 87s because the DVTs lack an ammeter.



Possibly superceded, but on one video of a 225 leaving King's Cross (15 exit limit), the driver pulled the power controller back halfway, released the brakes and as soon as the train moved pulled the handle fully back.

Ah, that explains the 10 'notch' marking power controller i've seen before then.

That technique doesn't seem completely implausible. I've noticed that some 225 drivers pull away quite quickly whilst others seem to crawl from a stand and you can hardly tell they're moving at first. Bare in mind that the brakes would still be releasing when that driver would have applied power so it wouldn't of been quite as much of a jerk as if the brakes had been fully released. Going from about 50% to 100% straight away seems like it would create a fairly noticeable jerk though so you're probably correct that this isn't done too often anymore.

 

[Kurolus Rex]

Actually I wonder if that's more in reference to HSTs? Notch 2 or 3 would be a typical enough notch to start one moving in.

I believe it might be. It wouldn't make much sense given how only the DVT has the markings for 'notches' and not the loco. I took a look at that section myself and couldn't find anything specifying what stock those guidelines were for. If you look hard enough you might find it written in small print but i think it's pretty safe to say it was referring to HSTs and not 225s.

 

[hexagon789]

Ah, that explains the 10 'notch' marking power controller i've seen before then.

That technique doesn't seem completely implausible. I've noticed that some 225 drivers pull away quite quickly whilst others seem to crawl from a stand and you can hardly tell they're moving at first. Bare in mind that the brakes would still be releasing when that driver would have applied power so it wouldn't of been quite as much of a jerk as if the brakes had been fully released. Going from about 50% to 100% straight away seems like it would create a fairly noticeable jerk though so you're probably correct that this isn't done too often anymore.

It was GNER days, but given that the original technique for opening up a 90 was going straight to full whack and letting the electronics sort everything out, it seems reasonable to assume that was carried over from BR.

I believe it might be. It wouldn't make much sense given how only the DVT has the markings for 'notches' and not the loco. I took a look at that section myself and couldn't find anything specifying what stock those guidelines were for. If you look hard enough you might find it written in small print but i think it's pretty safe to say it was referring to HSTs and not 225s.

I thought that as well, it makes more sense certainly.

 

[captainbigun]

What notches are these? 91s are notchless from initial (10% power). Unless they mean the markings of 1 to 10 on the DVT power controller, though that is still notchless and I assume a guide for if they were ever used with older tap changer locos such as 87s because the DVTs lack an ammeter.

Mk3 DVTs don’t have any markings as I recall, and it wouldn’t be relevant for an 86/87.

 

[superjohn]

I recall once reading that class 91 acceleration was electronically restricted for smoothness and passenger comfort. I have certainly never felt that ‘pushed back in the seat’ type acceleration that you can get with a class 87 or 90 on dry rails. That said, I have also read that this is down to the 110 v 140 mph gearing.

I do remember seeing a 91 running light engine through Peterborough back when they were first introduced. It was approaching a red signal on the down fast line and passed under the footbridge at a walking pace. The signal then cleared and it took off like a rocket! It really was car like acceleration and I haven’t seen anything like it since.

 

[The_Train]

It would be interesting to know if there is much difference between the loco end and the DVT end when it comes to driving too. Which do drivers prefer and why?

While enjoying a visit to the cab of 91119 at the All Change Open Day at Crewe, we asked the driver there which end drivers tended to prefer. He said that most would say the DVT end because it's quieter

 

[heedfan]

I do remember seeing a 91 running light engine through Peterborough back when they were first introduced. It was approaching a red signal on the down fast line and passed under the footbridge at a walking pace. The signal then cleared and it took off like a rocket! It really was car like acceleration and I haven’t seen anything like it since.

A light 91 is quite noticeably quicker to accelerate than a full set, even at depot speeds of 5mph. Without the speed limiter they would be quite a difficult loco to drive at such low speeds.

 

[hexagon789]

Mk3 DVTs don’t have any markings as I recall, and it wouldn’t be relevant for an 86/87.

I read that the Mk3 DVTs had markings put on the power controller to assist drivers when an 86/87 was on the back with taking power because the lack of an ammeter made it easier to accidentally overload the loco as it notched-up.

I assumed the Mk4 DVTs simply had this because they were built around the same time as the Mk3 DVTs rather than any plans to use them with 86/87s.

Though looking at a recent photo of a Mk3 DVT can, there are no markings on the power controller.

 

[EE Andy b1]

Mk3 and Mk4 DVT (Driving Van Trailer) cabs.



Only numbered on the Mk4 power controller (on the right).

 

[captainbigun]

I read that the Mk3 DVTs had markings put on the power controller to assist drivers when an 86/87 was on the back with taking power because the lack of an ammeter made it easier to accidentally overload the loco as it notched-up.

I assumed the Mk4 DVTs simply had this because they were built around the same time as the Mk3 DVTs rather than any plans to use them with 86/87s.

Though looking at a recent photo of a Mk3 DVT can, there are no markings on the power controller.

It’d make no sense to have 1-10 marked for use with 86/87, it’d bare no relation to the tapchanger position. Someone has got completely the wrong end of a stick with that description.

I described the method of control, high level, above. By design, assuming the loco is setup correctly you can fully open the DVT controller no matter what’s pushing. The loco will manage current levels.

 

[Bayum]

From the last few journeys I’ve made with LNER, it just seems to be gradual acceleration, then brake at the absolute last possible moment. I’ve felt pretty grim the amount of burning brake smell on some journeys

 

[krus_aragon]

From the last few journeys I’ve made with LNER, it just seems to be gradual acceleration, then brake at the absolute last possible moment. I’ve felt pretty grim the amount of burning brake smell on some journeys

Are LNER getting their money's worth out of the brake pads before they hand the fleet back?

 

[EE Andy b1]

The 87s shouldn’t overload when pushing, the demand is controlled based upon the actual current seen in the traction motors (using the highest of the four), more likely poorly setup overloads....which is a tricky job that takes time and patience.

I think then like you say the setup for overloading must have been wrong towards the end of Class 87 use on the West Coast, because 2 or 3 times driving from the DVT and applying full power you would get great acceleration then bang, traction light lost, the set would buffet about, shut off the power controller, wait then re-apply power again and away you go. Not great for passengers and staff when it did happen, not bad though considering TDM (Time Division Multiplex) was such a cheap system via RCH jumper cables.

 

[hexagon789]

It’d make no sense to have 1-10 marked for use with 86/87, it’d bare no relation to the tapchanger position. Someone has got completely the wrong end of a stick with that description.

My understanding aside from that was that the TDM was set up to demand a certain proportion of power from a tap-changer loco with the Mk3 DVTs. If the driver pulled the handle half-way back he would get half-power from the pushing loco.

I'll try and find the reference but it said something about notches being marked on the DVT controllers to aid drivers with not applying too much power too quickly.

 

[captainbigun]

The TDM doesn’t manage the demand, it’s purely communication. TE is 8 bits or 8 TDM channels, so effectively 256 steps. The TDM passes this on the same no matter what the slave is, be it a tap changer or thyristor loco or an HST power car for that matter. It’s the loco side processing that dictates the power application. On 86/87 that is the tractive effort translator (TET). It has a rough calculation in its software for current based upon the 8 bit input. It also has a max current, and that’s a way south of where the overload is set. TET notches up until demand is achieved or the max is hit based upon the current feedback. That loop is a little slow hence if there’s a poorly setup overload you may hit this before the TET has stopped notching.

 

[hexagon789]

The TDM doesn’t manage the demand, it’s purely communication. TE is 8 bits or 8 TDM channels, so effectively 256 steps. The TDM passes this on the same no matter what the slave is, be it a tap changer or thyristor loco or an HST power car for that matter. It’s the loco side processing that dictates the power application. On 86/87 that is the tractive effort translator (TET). It has a rough calculation in its software for current based upon the 8 bit input. It also has a max current, and that’s a way south of where the overload is set. TET notches up until demand is achieved based upon the current feedback. That loop is a little slow hence if there’s a poorly setup overload you may hit this before the TET has stopped notching.

Thank you for clarifying and explaining that, like so much information you find on the Internet, it's often rather incorrect which it must be been in the case or at least poorly worded to give a wrong impression.