steveintoronto
Superstar
Good description/comparison here on "balloon" loop v stub end x-over: https://en.wikipedia.org/wiki/Balloon_loop
Reminiscent of the "terminal v run-through" debate on rail stations, Toronto Union especially comes to mind on that. Just watching a CLRV lumber by here, and it dawned on me that the transition to pantograph operation drastically simplifies (with control system caveats and mu coupling) coupling single-ended cars back-to-back into multiple units that can reverse w/o loops. Needless to say, this his how ML is doing it on some LRT lines. With greater capacity from mu, headway would not be as demanding as single units, so the nature of operation would have to be complementary to realize the benefits v drawbacks.
Addendum: I have to wonder if a combination of both loop (mostly for single-ended) and a stub-track for reversible pairs could be an answer to the Union Station QQ east conundrum?
Perhaps even two stub tracks sharing an island platform, or one each side of the present tracks south of the loop to increase through-put for reversible consists?
From the link above:
[...]
Tram Systems[edit]
Balloon loops are used extensively on tramway systems with single-ended trams. Usually located at termini, the loop may be a single one-way track round a block. Single-ended trams have a cab at only one end and doors on one side, making them cheaper and having more space for passengers. On tram systems with double-ended trams balloon loops are not required but may still be used as they can provide greater turn-around capacity than a stub terminus; the Birmingham Corporation Tramways terminus at Rednal had a balloon loop in addition to the conventional stub tracks, providing extra capacity to handle weekend and bank holiday crowds visiting the nearby Lickey Hills. The Milan interurban tramway network, although using double-ended trams, had balloon loops at termini within the city limits so that they could be used as backup termini by the single directional trams used on urban service. In Milan, tramway depots are built as balloon loops, just as urban termini. Another example is in Potsdam, Germany.
[...]
Reminiscent of the "terminal v run-through" debate on rail stations, Toronto Union especially comes to mind on that. Just watching a CLRV lumber by here, and it dawned on me that the transition to pantograph operation drastically simplifies (with control system caveats and mu coupling) coupling single-ended cars back-to-back into multiple units that can reverse w/o loops. Needless to say, this his how ML is doing it on some LRT lines. With greater capacity from mu, headway would not be as demanding as single units, so the nature of operation would have to be complementary to realize the benefits v drawbacks.
Addendum: I have to wonder if a combination of both loop (mostly for single-ended) and a stub-track for reversible pairs could be an answer to the Union Station QQ east conundrum?
Perhaps even two stub tracks sharing an island platform, or one each side of the present tracks south of the loop to increase through-put for reversible consists?
From the link above:
[...]
Tram Systems[edit]
Balloon loops are used extensively on tramway systems with single-ended trams. Usually located at termini, the loop may be a single one-way track round a block. Single-ended trams have a cab at only one end and doors on one side, making them cheaper and having more space for passengers. On tram systems with double-ended trams balloon loops are not required but may still be used as they can provide greater turn-around capacity than a stub terminus; the Birmingham Corporation Tramways terminus at Rednal had a balloon loop in addition to the conventional stub tracks, providing extra capacity to handle weekend and bank holiday crowds visiting the nearby Lickey Hills. The Milan interurban tramway network, although using double-ended trams, had balloon loops at termini within the city limits so that they could be used as backup termini by the single directional trams used on urban service. In Milan, tramway depots are built as balloon loops, just as urban termini. Another example is in Potsdam, Germany.
[...]
Last edited: