4 line change in Bronx

[GreatOne2k]

8 minutes ago, T to Dyre Avenue said:

I almost feel like either the  model or (8) skip-stop are the only real options. Maybe it would be possible to have the  trains stop at 161st before going express, so that all  service stops there. 

Woodlawn -> Mosholu -> Burnside -> 167 - > 161 -> 149 is possible with track switching

[CenSin]

23 hours ago, GreatOne2k said:

Woodlawn -> Mosholu -> Burnside -> 167 - > 161 -> 149 is possible with track switching

A stop at Kingsbridge Road and 167 couldn’t hurt. The switches are already there.

[Lawrence St]

18 minutes ago, CenSin said:

A stop at Kingsbridge Road and 167 couldn’t hurt. The switches are already there.

Yeah but if we are doing the two trips during the rush, 167th/161st make no sense because it has to be rerouted back onto the express at 149th St to skip 138th St.

[T to Dyre Avenue]

Right. Express trains that have to switch to the local tracks to make a stop, then back to the express kind of defeats the purpose of running those trains express. 

[Jemorie]

41 minutes ago, T to Dyre Avenue said:

Right. Express trains that have to switch to the local tracks to make a stop, then back to the express kind of defeats the purpose of running those trains express. 

It's an utter waste of time too. It's completely unacceptable and should not be taken lightly either.

[CenSin]

52 minutes ago, T to Dyre Avenue said:

Right. Express trains that have to switch to the local tracks to make a stop, then back to the express kind of defeats the purpose of running those trains express. 

10 minutes ago, Jemorie said:

It's an utter waste of time too. It's completely unacceptable and should not be taken lightly either.

Don’t the trains already switch to the middle track anyway during those times to orchestrate a merge/diverge with the ? It would be 1 merge anyway. Kingsbridge Road through 167 Street would be the only segment where the and are on different tracks.

• Southbound, the trains would merge anyway whether it be at 167 Street or 149 Street–Grand Concourse. The doesn’t peel away from the again after either merge.
• Northbound, the trains would be on the same tracks at 149 Street–Grand Concourse. The question is whether the goes express right away or makes the stops at 161 Street and 167 Street first.

You can browse the track maps and see for yourself. There is no second split and merge. That would be awful.

[Lawrence St]

34 minutes ago, CenSin said:

Don’t the trains already switch to the middle track anyway during those times to orchestrate a merge/diverge with the ? It would be 1 merge anyway. Kingsbridge Road through 167 Street would be the only segment where the and are on different tracks.

• Southbound, the trains would merge anyway whether it be at 167 Street or 149 Street–Grand Concourse. The doesn’t peel away from the again after either merge.
• Northbound, the trains would be on the same tracks at 149 Street–Grand Concourse. The question is whether the goes express right away or makes the stops at 161 Street and 167 Street first.

You can browse the track maps and see for yourself. There is no second split and merge. That would be awful.

But some of these junctions have a lower MPH then others, at least from what I recall. 

[T to Dyre Avenue]

14 hours ago, CenSin said:

Don’t the trains already switch to the middle track anyway during those times to orchestrate a merge/diverge with the ? It would be 1 merge anyway. Kingsbridge Road through 167 Street would be the only segment where the and are on different tracks.

• Southbound, the trains would merge anyway whether it be at 167 Street or 149 Street–Grand Concourse. The doesn’t peel away from the again after either merge.
• Northbound, the trains would be on the same tracks at 149 Street–Grand Concourse. The question is whether the goes express right away or makes the stops at 161 Street and 167 Street first.

You can browse the track maps and see for yourself. There is no second split and merge. That would be awful.

Southbound  trains would merge out between Bedford and Kingsbridge. They would then merge back in with the  trains at either 167 or 149. But if the merge is at 167,  trains have to switch back to the local there, then both  and  trains have to switch to the middle before entering 149 to keep  trains moving. Now, you certainly could do this, but with all that extra switching, how much time would it really save over the current all-stop ? A merge between  and  at 149, would result in less switching and probably make for a slightly faster express, but at the expense of skipping busy 161. But then after under this scenario, the express would also be skipping Kingsbridge and Fordham. 

Meanwhile, a northbound  wouldn’t even be able to stop at Bedford because there’s no corresponding double crossover north of Kingsbridge that would allow northbound expresses to switch to local there. There is a switch that permits northbound local trains to switch to the middle, then the southbound local tracks using the southbound double crossover. But that’s so that train can access Concourse Yard, which is used to store some  trains. That’s probably why they don’t have a switch between the middle and the northbound local tracks at Kingsbridge, like they do southbound. Northbound  trains wouldn’t be able to switch until almost at Mosholu. That wouldn’t really be of much use. 

Edited January 4, 2020 by T to Dyre Avenue

[Union Tpke]

On 12/26/2019 at 5:31 PM, RR503 said:

Would be nice for connectivity, I guess, but would slam the  even moreso than today. Dunno if it should be pursued. 

I think that's exactly what should be done, but only after runtimes are stable (ie no more SPEED projects in the pipeline). I also think that the scheduled runtimes should be somewhat more aggressive than they are today so that the incentive to run a tight ship is maximized. 

I don't think you answered one of my questions. How aggressively should runtimes be?

[Lawrence St]

On 1/4/2020 at 10:30 AM, T to Dyre Avenue said:

Southbound  trains would merge out between Bedford and Kingsbridge. They would then merge back in with the  trains at either 167 or 149. But if the merge is at 167,  trains have to switch back to the local there, then both  and  trains have to switch to the middle before entering 149 to keep  trains moving. Now, you certainly could do this, but with all that extra switching, how much time would it really save over the current all-stop ? A merge between  and  at 149, would result in less switching and probably make for a slightly faster express, but at the expense of skipping busy 161. But then after under this scenario, the express would also be skipping Kingsbridge and Fordham. 

Meanwhile, a northbound  wouldn’t even be able to stop at Bedford because there’s no corresponding double crossover north of Kingsbridge that would allow northbound expresses to switch to local there. There is a switch that permits northbound local trains to switch to the middle, then the southbound local tracks using the southbound double crossover. But that’s so that train can access Concourse Yard, which is used to store some  trains. That’s probably why they don’t have a switch between the middle and the northbound local tracks at Kingsbridge, like they do southbound. Northbound  trains wouldn’t be able to switch until almost at Mosholu. That wouldn’t really be of much use. 

If Lexington Av is a major ridership corridor in the city, why would there be a need for these express trains to stop at 161st St? Since it's just a few trains, they should just run express directly to/from 149th St.

[Lex]

1 hour ago, Lawrence St said:

If Lexington Av is a major ridership corridor in the city, why would there be a need for these express trains to stop at 161st St? Since it's just a few trains, they should just run express directly to/from 149th St.

Because Jerome is no slouch, least of all at that point. Any express proposal misses much of the ridership, defeating the purpose.

[RR503]

On 3/15/2020 at 12:14 PM, Union Tpke said:

I don't think you answered one of my questions. How aggressively should runtimes be?

Well what you should really do is break runtimes out into its components: runtime and dwell. Then try to figure out components: how much of this runtime is holds to time? What about controllable dwells? etc, and then you go ahead and schedule around median runtime, but without those confounding components in the mix.