Fantasy: Power car on both ends on a IC225 set?

[Sad Sprinter]

Years ago I made a Microsoft Train Simulator activity revolving around a "test train" from Bounds Green to York with a modified IC225 formation that had a class 91 on each end. So the entire rake looked like a Eurostar or IC125. The idea was that the player was meant to use this extra power in order to achieve +140mph running along the straighter parts of the line.

I've always wondered in reality, what the effect on performance would be with a double-powered IC225 set. Would it be able to achieve higher speeds or just accelerate more quickly to the same top speed?

 

[Doomotron]

You wouldn't be able to in real life, at least in the way you described. Mark 4 sets are effectively fixed formations. At one end there has to be the DVT and at the other end there needs to be the rear coach (I don't know the classification of it, but it's the one with no gangway). I'm not aware if it's possible to have one of those rear coaches at both ends, but assuming the Mark 4 DVT works in the same way as a Mark 3 DVT or Mark 2 DBSO, braking equipment is kept in the DVT which means one is essential for the train to function. If this is the case, a formation like the one in your post would need to have a 91 in front of the DVT which would ruin the look you're going for.

Again I'm not certain about the requirements for Mark 4 sets but this is what I believe to be the case.

 

[CarrotPie]

At one end there has to be the DVT and at the other end there needs to be the rear coach (I don't know the classification of it, but it's the one with no gangway).

Open Disabled Standard (End) - according to my Platform 5 pocket book

 

[Sad Sprinter]

You wouldn't be able to in real life, at least in the way you described. Mark 4 sets are effectively fixed formations. At one end there has to be the DVT and at the other end there needs to be the rear coach (I don't know the classification of it, but it's the one with no gangway). I'm not aware if it's possible to have one of those rear coaches at both ends, but assuming the Mark 4 DVT works in the same way as a Mark 3 DVT or Mark 2 DBSO, braking equipment is kept in the DVT which means one is essential for the train to function. If this is the case, a formation like the one in your post would need to have a 91 in front of the DVT which would ruin the look you're going for.

Again I'm not certain about the requirements for Mark 4 sets but this is what I believe to be the case.

Oh I see, what if the breaking mechanism was transferred into one of the coaches? Or a new MK4 Brake van?

 

[hexagon789]

I don't know the classification of it, but it's the one with no gangway

Open Disabled (End)

TOE - Tourist Open End

Oh I see, what if the breaking mechanism was transferred into one of the coaches? Or a new MK4 Brake van?

It's the requirement for a handbrake, technically a 91 fulfils this.

The other requirement is dual actuation of the air brake at over 110mph, on HSTs each power car applies the brake simultaneously (the rear one is signalled electrically from the front).

Similarly on 225s, the brake is applied from both ends with either the 91 signalling the DVT or vice-versa. Again a second 91 should be able to work the high-speed brake like this.

Really for testing the two problems I see are:

- power supply (power draw of two 91s)
- braking distance (even with Flashing Greens, this was a bit tight at 140mph in poor rail conditions).

 

[Sad Sprinter]

- braking distance (even with Flashing Greens, this was a bit tight at 140mph in poor rail conditions).

Would the formation have too much power and need stronger brakes?

 

[43096]

Open Disabled (End)

No. It’s the TOE - Tourist Open End.

 

[43096]

The other requirement is dual actuation of the air brake at over 110mph, on HSTs each power car applies the brake simultaneously (the rear one is signalled electrically from the front).

Similarly on 225s, the brake is applied from both ends with either the 91 signalling the DVT or vice-versa. Again a second 91 should be able to work the high-speed brake like this.

HST power cars have either an E70 or DW2 brake pipe pressure control unit , which is actuated remotely as you say over the 36 way jumper cable. For the 91+Mark 4 DVT (and indeed also Class 90 and Mark 3 DVT) activation of the remote E70 or DW3 is similar but over the TDM system.

 

[driverd]

You wouldn't be able to in real life, at least in the way you described. Mark 4 sets are effectively fixed formations. At one end there has to be the DVT and at the other end there needs to be the rear coach (I don't know the classification of it, but it's the one with no gangway).

I'm not saying you're wrong here (I've never worked with Mk4s) but what's your basis for this?

It was my understanding that Mk4s were essentially the same as any other coaching stock and there's nothing special about the TOE or DVT that would prevent the vehicles moving without them. Each has a brake res and distributor, all you'd need to do is find an appropriately coupler fitted loco with a red and yellow pipe and off you go with any formation. Providing ETS is another matter.

I'm not aware if it's possible to have one of those rear coaches at both ends, but assuming the Mark 4 DVT works in the same way as a Mark 3 DVT or Mark 2 DBSO, braking equipment is kept in the DVT which means one is essential for the train to function. If this is the case, a formation like the one in your post would need to have a 91 in front of the DVT which would ruin the look you're going for.

If its like a Mk3 or Mk2 it has the same brake equipment as the coaches, plus a brake frame (which connects to the brake valve). This can all be isolated and allow the vehicle to run as a standard coach - note also a DBSO or Mk3 DVT is not essential for a Mk2 or Mk3 rake.

It's the requirement for a handbrake, technically a 91 fulfils this.

The other requirement is dual actuation of the air brake at over 110mph, on HSTs each power car applies the brake simultaneously (the rear one is signalled electrically from the front).

Similarly on 225s, the brake is applied from both ends with either the 91 signalling the DVT or vice-versa. Again a second 91 should be able to work the high-speed brake like this.

Really for testing the two problems I see are:

- power supply (power draw of two 91s)
- braking distance (even with Flashing Greens, this was a bit tight at 140mph in poor rail conditions).

...which seems to address the above.

As far as I'm aware, wasn't the original plan always for 140mph with 1x 91 anyway?

With 2, you'd have double the HP, so power supply constraints aside, I imagine you'd be able to achieve a higher top speed. As noted above, however, finding appropriate infrastructure for such speeds may be challenging.

Unfortunately this is one of the downfalls of train simulator. Even with add ons and modifications, it's still far too much designed as a game. It doesn't have anything like the physics engines of some flight simulators so can't really teach you anything meaningful about "what ifs".

I can't imagine the ride would be great for the pax either!

 

[43096]

I'm not saying you're wrong here (I've never worked with Mk4s) but what's your basis for this?

It was my understanding that Mk4s were essentially the same as any other coaching stock and there's nothing special about the TOE or DVT that would prevent the vehicles moving without them. Each has a brake res and distributor, all you'd need to do is find an appropriately coupler fitted loco with a red and yellow pipe and off you go with any formation. Providing ETS is another matter.

The issue is couplers. Only the TOE and DVT have buffers, screw coupler hooks and (for the TOE) a drop head buckeye for coupling to a loco. The inner end of the TOE and DVT and all the intermediate vehicles have Tightlock couplers that can’t be coupled directly to a Class 91 or any other loco.

 

[Sun Chariot]

Years ago I made a Microsoft Train Simulator ... with a modified IC225 formation that had a class 91 on each end ... I've always wondered in reality, what the effect on performance would be with a double-powered IC225 set.

The traction's top speed will still be limited by its gearing and the track alignment. Acceleration, however, will increase (due to a higher power-to-weight ratio).

in late 1980s, prior to the full introduction of Mk4s, the 91s ran with Mk3s + class 43 (surrogate DVT). I rode a Leeds-London service where both 91 and 43 were using all their available power. The acceleration was very impressive!

 

[hexagon789]

Would the formation have too much power and need stronger brakes?

You could end up exceeding the practical limits of adhesion - ie the wheels lock up under braking and the train slides.

As far as I'm aware, wasn't the original plan always for 140mph with 1x 91 anyway?

For the IC225, yes.

The APT-S I believe was going to have two Class 91-esque power cars, one each end.

I assume they would've had the same 4,000hp of the prototype APT power cars and not the 6,088hp of the Class 91.

 

[Sad Sprinter]

APT-S

Thanks for that, your comment led me down the weird and wonderful rabbit hole of APT formations on this website: APTConfigurations.htm

Never knew there were so many variants planned. The ones with the power car next to DVT look particularly impressive!

 

[hexagon789]

Thanks for that, your comment led me down the weird and wonderful rabbit hole of APT formations on this website: APTConfigurations.htm

Never knew there were so many variants planned. The ones with the power car next to DVT look particularly impressive!

Indeed, and I see it was actually the U and V variants with an electric power car each end; the S having a driving trailer and being quite similar to how the 225 sets turned out.

 

[themiller]

A pair of 91s tnt a rake of coaches may need modifications to the overhead conductors if both pantographs are up to minimise bounce on the rear one. Bounce in the overheads could affect trains on adjacent tracks through the headspans.

 

[AdamWW]

You could end up exceeding the practical limits of adhesion - ie the wheels lock up under braking and the train slides.

Why would adding more power (so greater acceleration) do this?

It was my understanding that Mk4s were essentially the same as any other coaching stock and there's nothing special about the TOE or DVT that would prevent the vehicles moving without them. Each has a brake res and distributor, all you'd need to do is find an appropriately coupler fitted loco with a red and yellow pipe and off you go with any formation. Providing ETS is another matter.

I believe the gangway connections and couplers are non standard so unlike coaches up to Mk3 they couldn't be mixed and matched with other types, but didn't they (unlike HST MK3s) use regular ETS? I'm pretty sure that they used to diesel haul them on diversion. And the 91's were originally supposed to be hauling sleeper trains among othher things at night so if they provide some special ETS they'd have to provide the regular version too.

A pair of 91s tnt a rake of coaches may need modifications to the overhead conductors if both pantographs are up to minimise bounce on the rear one. Bounce in the overheads could affect trains on adjacent tracks through the headspans.

Just bung a 25 kV cable over the coach roofs.

 

[DanNCL]

A pair of 91s tnt a rake of coaches may need modifications to the overhead conductors if both pantographs are up to minimise bounce on the rear one. Bounce in the overheads could affect trains on adjacent tracks through the headspans.

The modifications required have already been done to allow 10 car 80x formations to run with two pantographs up.

 

[hexagon789]

Why would adding more power (so greater acceleration) do this?

The OP said 'stronger brakes'.

It is already easy enough to go into a slide with the 9%g full service braking rate the 225 sets have , let alone the 10%g rate of 80x or the 12%g emergency rate most post-1990s traction has.

The APT-P hydrokinetic brake achieved a 15%g braking rate but controlling high-speed wheelslide effectively under such braking rates proved very difficult.

 

[TT-ONR-NRN]

Besides, you say it'd be so they can achieve 140mph, but they already can do. They were designed to do this, and only don't because speeds like that require major signalling upgrades and additional in cab signalling. Same for the 390s here.

 

[hexagon789]

Besides, you say it'd be so they can achieve 140mph, but they already can do. They were designed to do this, and only don't because speeds like that require major signalling upgrades and additional in cab signalling. Same for the 390s here.

140mph/225km/h is technically the in-service speed (though of course limited to 125mph by signalling contraints), they were in-fact designed for 150mph/240km/h - the specification called for this:

 

[AdamWW]

The OP said 'stronger brakes'.

Ah fair enough.

I don't see why adding more power to the train would necessitate stronger brakes though.

 

[Sad Sprinter]

Besides, you say it'd be so they can achieve 140mph, but they already can do. They were designed to do this, and only don't because speeds like that require major signalling upgrades and additional in cab signalling. Same for the 390s here.

Well my thinking was could a double powered set achieve 160 mph+ speed and accelerate there quicker.

 

[Sun Chariot]

Well my thinking was could a double powered set achieve 160 mph+ speed and accelerate there quicker.

Post #11 hopefully explains

 

[hexagon789]

Ah fair enough.

I don't see why adding more power to the train would necessitate stronger brakes though.

A higher top speed, if the available braking distance was not increased, would require greater braking power and a higher deceleration rate like the APT-P.

That was my thinking anyway.

 

[AdamWW]

A higher top speed, if the available braking distance was not increased, would require greater braking power and a higher deceleration rate like the APT-P.

That was my thinking anyway.

Yes I hadn't realised the idea was to go above 140 mph (even though the infrastructure wouldn't cope with it for various reasons).

I suppose in principle a higher top speed doesn't have to require better braking in normal operation if you just provide more time to slow down before a red signal.

 

[hexagon789]

I suppose in principle a higher top speed doesn't have to require better braking in normal operation if you just provide more time to slow down before a red signal.

The IC225 of course was going to require an additional signal block for 140mph operation, and the braking system was also set-up as two-stage with a reduced braking rate above 125mph.

 

[Ken H]

The IC225 of course was going to require an additional signal block for 140mph operation, and the braking system was also set-up as two-stage with a reduced braking rate above 125mph.

Thats what the flashing greens were for. From memory flashing green = next signal is green. Green = next signal may be green. Or not. So speed restricted to 125mph.

 

[randyrippley]

I've mentioned this before, but one real-life example I've always wondered about was a test lashup I saw heading up the WCML at Galgate in (I think) 1978. Essentially two APT-P power cars, led by one of the prototype HST power cars with dynamometer coach and a couple of test coaches (I think one was the coach with the pantograph monitoring camera).
Both APT cars had the pantographs raised so were presumably powered, while the HST car was definitely working hard.
I've always wondered what speed that setup could have achieved.
I guess it's possible the APT cars were running dead and they were just checking the catenary/pantograph interaction with both raised. Disappointing if that's the case

 

[gingertom]

I envisioned a while back taking 2x IC225 rakes, turn one around, remove both DVTs and stick them together. Perhaps remove one rake's first class coaches and maybe one of the kitchen cars and you'd end up with a 2+14/15 formation. Significantly less weight to move about, 12,600BHP on tap, so higher acceleration. Then all the issues of pantograph bounce, double the current take from the OLE, couplers, ETH etc mentioned upthread come into play. Technical issues can be overcome with a little bit of engineering (and lot of money!) Then which platforms could actually use them?

 

[Deepgreen]

The principle here is, I imagine, the same as with any 'super-power' formations - there is more power (more or less double with a 91 at each end) to overcome wind resistance at high speeds so that may add a little, but the governing issue for top speed will always be the gearing of the traction. A 91 has got to 162mph (I think) and I don't know if that was re-geared specially. The acceleration would be far greater, of course.