REM - Matériel Roulant

[SameGuy]

Please tell me you’ve actually been on the ones in Paris and Barcelona you’re claiming are horrible. And again, what about the ride quality? You countered my original claim that “modern steel-on-steel metros ride more comfortably than any rubber-tired metro” by dishing out the straw man that “steel wheels screech incessantly” (also untrue). Watch this again, a new Paris metro train running on an old line (1908) and tell me you hear any screeching or “tak tak” over rail joints. The only thumping is over a switch entering the station, and the only reason you hear it is because the train is so quiet to begin with. On the Montreal Metro you can’t even hear yourself think. But the ride quality? Come on, man. Stop trolling.

 

[Rocco]

5 minutes ago, SameGuy said:

Please tell me you’ve actually been on the ones in Paris and Barcelona you’re claiming are horrible. And again, what about the ride quality? You countered my original claim that “modern steel-on-steel metros ride more comfortably than any rubber-tired metro” by dishing out the straw man that “steel wheels screech incessantly” (also untrue). Watch this again, a new Paris metro train running on an old line (1908) and tell me you hear any screeching or “tak tak” over rail joints. The only thumping is over a switch entering the station, and the only reason you hear it is because the train is so quiet to begin with. On the Montreal Metro you can’t even hear yourself think. But the ride quality? Come on, man. Stop trolling.

 

I've riden every single one of them. I even forgot Boston. Horrible too. All on steel. Im not saying they screetch 100% of the time. Of course if they run in straight line between 2 stations its gonna be somewhat smooth. But the minute they put the brakes to enter a station, or take a small turn in a curved section, screetching starts. And they often halts in the middle of a tunnel, for no specific reason. We dont have that in Montreal. Putting the brakes entering a station is smooth as butter. 

[SameGuy]

You’re still telling me “rubber is smoother than steel because steel screeches.” Straw man. We’re done here. 

[SameGuy]

Barcelona Line 9. Alstom Metropolis driverless trains. 86 m long, overhead catenary. Similar in most respects to REM-A (except for open gangways throughout, like Sydney). No driver cab — the below video is from the “front vitrine” inside the train. If anyone tells me it’s not as smooth as Montreal, or it’s screeching too much… I have nothing left to say.

 

[Rocco]

5 minutes ago, SameGuy said:

Barcelona Line 9. Alstom Metropolis driverless trains. 86 m long, overhead catenary. Similar in most respects to REM-A (except for open gangways throughout, like Sydney). No driver cab — the below video is from the “front vitrine” inside the train. If anyone tells me it’s not as smooth as Montreal, or it’s screeching too much… I have nothing left to say.

 

Interesting! Love those front row train videos. Very smooth indeed! 👍 There's hope for the REM.

[SameGuy]

I’m still fascinated by the large, single-bore tunnel with stacked stations platforms within the tunnel bore itself. It was the main thrust of the original Pink Line proposal. Long elevators on most of the 30+ stations would suck dead monkey balls, though. Maybe they could borrow the technique St-Petersburg used, diagonal bores for looooooong escalators.

[Enalung]

5 hours ago, SameGuy said:

Please tell me you’ve actually been on the ones in Paris and Barcelona you’re claiming are horrible. And again, what about the ride quality? You countered my original claim that “modern steel-on-steel metros ride more comfortably than any rubber-tired metro” by dishing out the straw man that “steel wheels screech incessantly” (also untrue). Watch this again, a new Paris metro train running on an old line (1908) and tell me you hear any screeching or “tak tak” over rail joints. The only thumping is over a switch entering the station, and the only reason you hear it is because the train is so quiet to begin with. On the Montreal Metro you can’t even hear yourself think. But the ride quality? Come on, man. Stop trolling.

 

The short answer is that there are no rail joints on modern railways. It's all welded rails, 300 meters long, with joints welded using thermite which forms a single continuous rail from one end to the other. Also, the part of the train which causes screeching is the flange. Modern trains have all but eliminated the flange, instead opting for conical wheels. The reason that simple conical wheels work is hunting oscillation. Basically, the the train is always being brought back to it's center of mass as is moves.

[SameGuy]

Yup. That’s why I don’t understand the comments above.

[Gaston]

Le 2021-02-24 à 14:42, Enalung a dit :

The short answer is that there are no rail joints on modern railways. It's all welded rails, 300 meters long, with joints welded using thermite which forms a single continuous rail from one end to the other. Also, the part of the train which causes screeching is the flange. Modern trains have all but eliminated the flange, instead opting for conical wheels. The reason that simple conical wheels work is hunting oscillation. Basically, the the train is always being brought back to it's center of mass as is moves.

Long answer is a lot of subways still do not use 300m long welded rails and they will never use it! What I was trying to say all along is that comparing a subway line like line 1/4 of paris compared to the GPE makes no sense! It is like comparing an LGV with a connection railway line!

Regarding the wheels, wheels have been conical for nearly 100 years, the problem of the squeaking usually happens in tight curves that are tighter than recommended for the wheels! So the flange touches the rail. For example, high speed trains have a tendency to squeak a bit more when you get to the station compared to the standard trains because the cone angle on the wheel is shallower.

But this subject seems to be pissing off people so I won't talk about it anymore.

Modifié 1 mars 2021 par Gaston
precision

[champdemars]

Je suis allé à Ottawa en fin de semaine, j’en profité pour essayer leur « métro léger » (entre guillemets puisque c’est techniquement un système de métro mais avec des rames de tramways)

Et parlant des rames... elles grincent pas mal je trouve dans les courbes. C’est assez agressant. Est-ce à cause du plancher bas qu’on ressent à ce point les courbes?

Je me demandais si le plancher haut du REM allait éviter ça.