Tilt Mechanism

[CSXfoamer1997]

Does anyone know of any reasons why trainsets were designed with tilt mechanism, but NOT standard loco-hauled trains? I personally think that passenger locos as well as detachable cars should be fitted with tilt mechanism.

 

[CCC1007]

Because there needs to be coordination, and track spacing concerns in some areas would limit their use. Tilt would only work on a dedicated set, any other cars would force tilting technology to shut down.

Tilt mechanisms also increase maintenance costs and down time.

 

[ScouseAndy]

The British Rail APT would have been a loco hauled tilting train had it made production, the BR Class 91 locomotive was originally also meant to have active tilt but this was removed, the Class 93 design brief was for it to have active tilt but this never even got off the drawing board.

In western Europe Loco hauled services for passenger services have fallen out of fashion and in China they too are going down the Multiple Unit route for high speed trains so unless by some miracle Amtrak get some serious funding I cant see any country using loco hauled active tilt high speed services in the near to medium future.

 

[jis]

Moving away from loco hauled to D/EMUs, specially for higher speed service is an almost across the world phenomenon. Even India is in the process of acquiring EMUs for the higher speed prestige inter-city trains. They just perform so much better than loco hauled equipment that it is almost no contest. By merely replacing loco hauled equipment by EMU distributed power equipment IR thinks they can lop off a cool 2 hours from the effective end to end schedule on the 900 mile + trunk routes purely from better acceleration/deceleration performance. On these congested routes there is a lot of acceleration and deceleration for adverse signals, PSRs and TSRs in addition to the station stops, and some involve upto 2.5% grades. The future clearly points towards DMUs and EMUs.

 

[railiner]

The future is clearly pointing towards high speed EMU's? Where have I heard that before....?

Oh yeah......Metroliner's!

 

[jis]

Since the US is unlikely have any high speed trains we need not worry our heads about it to much in general.

And whatever high speed trains do materialize will most likely be EMUs (distributed power) anyway.

 

[ScouseAndy]

The future is clearly pointing towards high speed EMU's? Where have I heard that before....?

Oh yeah......Metroliner's!

Try looking at what we are doing in Europe, then look at what china is doing and what Japan has done since the 70's, theres only 1 nation who seems to think they are right and the rest of the world is wrong.

 

[jis]

The original Metroliner project was US's cheap fix to be able to claim that we are as good as Japan. They ignored everything that Japan learned and fed back into the development of their robust high speed program. We got the quick fix, and then got stuck there for the next 30 years, while not only Japan, but the world passed us by. The Brits started after us and produce a world class 125mph diesel semi-articulated set which runs to this day. We did not even try. We got a Turbotrain which we could not run for too long. They then developed DMUs and DEMUs that run at 125mph, we did not even try. To believe that US has any expertise at all to actually produce a working high speed train without importing almost all of the technology from abroad at this point would appear to be borderline laughable.

Initially the Japanese thought they needed to take the US experience into consideration. They came to visit the NEC during the period when Metroliners were being developed. They couldn't believe what they saw. They went back home shaking their heads in disbelief and then did not come back again until the time when they felt they should invest and set up their own HSR in the US if at all possible. We have been resisting that mightily every which way we can too. Clearly the Acela exercise has impressed absolutely no one except a few in the US. Anyway, this EMU discussion probably belongs somewhere else, not in this thread.

Meanwhile as Trump says in one of his moments of sanity - our trains go chug chug chug

 

[seat38a]

How does the Talgo on the Cascades work? I thought those trains tilt.

 

[cirdan]

Initially the Japanese thought they needed to take the US experience into consideration. They came to visit the NEC during the period when Metroliners were being developed. They couldn't believe what they saw. They went back home shaking their heads in disbelief and then did not come back again until the time when they felt they should invest and set up their own HSR in the US if at all possible. We have been resisting that mightily every which way we can too. Clearly the Acela exercise has impressed absolutely no one except a few in the US. Anyway, this EMU discussion probably belongs somewhere else, not in this thread.

I was told by a Japanese railfan that the Japanese actually took a lot of inspiration from Germany. What later became the Shinkansen was in its earliest planning incarnation, way back in the 1930s, going to be a German style streamlined dmu train similar to the Flying Hamburger. A Japanese delegation visited Germany and inspected said trains for this purpose.

 

[cirdan]

How does the Talgo on the Cascades work? I thought those trains tilt.

They do.

They use passive titling technology which is a half way house between no tilt and active tilt, both in terms of the technological complexity and of the speed leverage.

 

[PerRock]

How does the Talgo on the Cascades work? I thought those trains tilt.

They use a passive tilt system, rather then an active tilt (like most HSR trains). But in essence, yes they tilt and their locomotives (here in the states) don't tilt. I'm sure there are other examples of this type of system out there as well.

peter

 

[cirdan]

How does the Talgo on the Cascades work? I thought those trains tilt.

They use a passive tilt system, rather then an active tilt (like most HSR trains). But in essence, yes they tilt and their locomotives (here in the states) don't tilt. I'm sure there are other examples of this type of system out there as well.

peter

Seeing tilt is about comfort rather than safety, there is no pressing need for locomotives to tilt, or indeed non passenger carrying cars.

 

[jis]

Actually most HSR trains and specially the really HSR ones do not have any tilt system. Some of the slightly slower HSR trains have tilt systems.

 

[Metra Electric Rider]

I thought a big part of the reasoning for tilting trains (Talgo especially) was to enable increased speeds comfortably on unmodified tracks, is that an incorrect rationale?

 

[jis]

I thought a big part of the reasoning for tilting trains (Talgo especially) was to enable increased speeds comfortably on unmodified tracks, is that an incorrect rationale?

That, together with much higher underbalance allowed on curves in Europe makes it very useful on twisty turny existing tracks duly upgraded to take the higher speed. They, and other tilting sets are not as effective in the US due to FRA enforced restrictions on underbalance, but still help quite a bit.

True HSR on new HSR tracks naturally do not have much use for tilt, which just adds weight and makes the ride a little rougher, since their tracks are straight enough to start with.

 

[railiner]

I thought a big part of the reasoning for tilting trains (Talgo especially) was to enable increased speeds comfortably on unmodified tracks, is that an incorrect rationale?

Exactly....while the tilt does not make taking curves on a flat track safer for the equipment, it does make it more comfortable for the passenger, as the centrifugal force will 'press' the passenger down towards the floor, rather than out towards the side of the car....

 

[cirdan]

I thought a big part of the reasoning for tilting trains (Talgo especially) was to enable increased speeds comfortably on unmodified tracks, is that an incorrect rationale?

Partially true.

The speed of a train in a curve is limited by four factors

1) passenger comfort, This can be alleviated by tilting

2) perpendicular track forces that can lead to increased wear on the rail, push the track out of alignment, or worse still, cause the wheel to climb the rail and derail. This can be alleviated by restricting the axle loading and seeking a low center of gravity. Tilting trains are generally lighter than regular trains. Talgo especially so

3) operational restrictions such as imposed by signalling distances, visibility, These need to be resolved by capital investments.

4) the track itself. If this is totally rickety, even the most hi-tech train in the world can't go much faster on it without endangering safety. Again, this needs capital investment

Many railroads have seen tilting trains as a quick fix and a low cost alternative to proper HSR, but by addressing some but not all of these points have failed to deliver the hoped for benefits, and thus end up with an expensive train running a schedule that a cheaper rnormal train could have done just as well.

This is not so much a problem in the US with its generous clearences but in Europe and especially the UK, tilting trains need to be narower than regular trains to allow space for the tilt and this leads to a compromised interior design with many users now viewing tilting trains as an inferior solution from the passenger perspective.

So in summary, if done properly, tilting trains can be a wonderful thing, but if not done properly they can be quite a botched job.

The initial inspiration behing the Talgo was by the way not about tilting. In fact the early generations of Talgo train did not tilt. It was originally about creating an ultra-lightweight train that could accelerate quickly with a low-powered locomotive.