Open and closed blocks

Note: The combination of e-mobility and open line blocks is methodologically problematic because in this case, it is not possible to check whether the vehicle can be charged sufficiently to provide the intended services by the time it is used the next day. We therefore recommend forming only closed blocks for e-mobility.

Independent of the selected calendar type, open and closed blocks can be generated. Open blocks start on the first day of the line blocking time period (or later) and end by the latest on the last day. For closed blocks, the last day is again followed by the first day of the line blocking time period, so that each end of a sequence of line block items is connected with a start. This ring closure is analog to timetable-based public transport assignment and is used to include the costs for creating the initial situation into the model. The creation of closed blocks assures that the created line block schedule "in perpetuo" can be traversed. The following example with an extremely unsymmetrical timetable makes this clear.

Image 191: Unsymmetrical timetable with trips beyond 24 hours

If open blocks are created in this example, then one vehicle is sufficient, because the trip from A Village to X City plus the empty trip in the opposing direction will require 66 minutes and the departure of this cycle in A village is every 2 hours. The vehicle can therefore reach the starting point before the start of the next trip.

When creating closed blocks however, two vehicles are required. The reason for this lies in the last trip, which is scheduled for 26:05 and thus still belongs to the previous day. Only one hour lies between the departure of this vehicle journey and the subsequent first trip on next day, so that the vehicle cannot return to the starting point in the meantime. When creating open blocks, this transition to the following day is not regarded, which may result in underestimating the vehicle demand.

Apart from the pure vehicle demand, the open block solution of course has one empty trip less. If costs are evaluated for empty trips, this solution also simulates a less expensive situation. In each case it has to be decided, whether the empty trip which is required to form the ring closure has to be included in the model or not.

Note: Open blocks can be created if the model represents the planning situation for a certain single day or period. If the line blocking time period however, represents a longer cycle which is to be repeated (for example a default day), closed blocks should be created, to correctly determine the costs for restoring the initial state in the model.

Table 216: Open block and closed block for the unsymmetrical example (Image 191)

Block no.

Block version code

Number of block days

Block closed

Mean operating time

Mean operating kilometers

1

OpenBlocks

1

0

12h 51min

616

2

Self-ContainedBlocks

2

1

6h 36min

321

Block no.

Index

Blocking day

Block item type

Line name

Vehicle journey no.

Start time

From StopPointName

End time

To StopPointName

1

1

1

Vehicle journey

BUS1

16

03:05:00

A-Village

03:50:00

X-City

1

2

1

Empty trip

 

0

3.50

X-City

04:11:00

A-Village

1

3

1

Layover

 

0

04:11:00

A-Village

05:05:00

A-Village

1

4

1

Vehicle journey

BUS1

18

05:05:00

A-Village

05:50:00

X-City

1

5

1

Empty trip

 

0

5:50:00 AM

X-City

06:11:00

A-Village

1

6

1

Layover

 

0

06:11:00

A-Village

07:05:00

A-Village

...

...

...

...

...

...

...

...

...

...

1

31

1

Vehicle journey

BUS1

36

23:05:00

A-Village

23:50:00

X-City

1

32

1

Empty trip

 

0

23:50:00

X-City

00:11:00

A-Village

1

33

1

Layover

 

0

00:11:00

A-Village

02:05:00

A-Village

1

34

1

Vehicle journey

BUS1

37

02:05:00

A-Village

02:50:00

X-City

2

1

1

Layover

 

 

00:11:00

A-Village

02:05:00

A-Village

2

2

1

Vehicle journey

BUS1

37

02:05:00

A-Village

02:50:00

X-City

2

3

1

Empty trip

 

0

02:50:00

X-City

03:11:00

A-Village

2

4

1

Layover

 

0

03:11:00

A-Village

00:00:00

A-Village

2

5

2

Layover

 

0

00:00:00

A-Village

03:05:00

A-Village

2

6

2

Vehicle journey

BUS1

16

03:05:00

A-Village

03:50:00

X-City

2

7

2

Empty trip

 

0

3.50

X-City

04:11:00

A-Village

2

8

2

Layover

 

0

04:11:00

A-Village

05:05:00

A-Village

2

9

2

Vehicle journey

BUS1

18

05:05:00

A-Village

05:50:00

X-City

2

10

2

Empty trip

 

0

05:50:00

X-City

06:11:00

A-Village

2

11

2

Layover

 

0

06:11:00

A-Village

07:05:00

A-Village

...

...

...

...

...

...

...

...

...

...

2

36

2

Vehicle journey

BUS1

36

23:05:00

A-Village

23:50:00

X-City

2

37

2

Empty trip

 

0

23:50:00

X-City

00:11:00

A-Village

Table 217: Block items of both blocks in the example – Block items in the recurring rhythm were omitted for a better overview. Block 1 is open, block 2 is closed.