7. CVRP by savings heuristic: Dabbawala network In Mumbai Dabbawala network In Mumbai, most office goers prefer to eat home-cooked food rather than eat out, usually for reasons of taste and hygiene, hence the concept. A number of workfrom-home women also supply such home-cooked meals, delivering through the dabbawala network. The word dabbawalla comes from the Hindiwords dabba(tiffin) and walla (delivery man). A dabbawala (also spelled dabbawalla or dabbawallah) is a person in India, most commonly in Mumbai, who is a part of a delivery system which collects hot food in lunch boxes in late morning from workers residences, delivers lunches to the workplace utilizing various modes of transport, predominantly bicycles and trains, and returns the empty boxes to the customers residences in the afternoon. They are also made use of by prominent meal suppliers in Mumbai, where they ferry ready-cooked meals from central kitchens to customers. The dabbawala is required to wear a white cap during business hours and is also required to carry an identity card for easy identification. Every dabbawala is well accustomed to the local areas they cater to. This allows them to easily access any destination. Both the customer and the dabbawalas are well known to each other; so there is no question of lack of trust. To satisfy their customers, they use a complex system of collection teams, sorting points and delivery zones and a completely manual system for routing the right meal to the right destination. The dabbawala food delivery system allows an office worker to eat home-cooked lunches, by offering a delivery of a tiffin from his home to his office. The delivery service started in 1890 with only one person. Since its foundation the organization grew to become a registered charitable trust in 1956. At present the organization numbers about 5,000 employees, who deliver about 400,000 tiffins every day (including returns). The dabbawala collects the tiffin at around 9 a.m. from the customers home. It is then transported to the nearest train station, sorted, grouped with other tiffins, delivered to the destination station, sorted again and finally delivered by bicycle directly to the office. In the afternoon the dabbawala collects the empty tiffin container which is then delivered back to the customers home. Tiffins are sorted by a system of colour coding that indicates the home and office as well as the related train stations. The colour code is needed because the average literacy rate of a dabbawala is eighth-grade schooling; many are fully illiterate (Agrawal 2011). The colour-coding system identifies the destination and recipient. Lunch boxes are usually marked in several ways: (1) abbreviations for collection points; (2) colour code for starting station; (3) number for destination station; and (4) markings for the handling dabbawala at destination, building and floor. The dabbawalas performance is special, especially when Mumbais traffic is taken into account. The average distance an inhabitant of Mumbai travels to work/school does not differ much from for example the distance travelled in Berlin (17.5km to 16.2km). But while someone in Berlin needs an overall 42 minutes for the trip, a person in Mumbai needs about 70 minutes (NUMBEO 2014). This leaves a dabbawala with the challenge of delivering the tiffin as quickly as possible, so that the food is still hot when it arrives. The dabbawala networks error rate is one in 16 million transactions, making it a very reliable system. This is special because the system started as a bottom-up system without any head organization and today consists of many illiterate employees (Agrawal 2011). In 2001 the Forbes Magazine awarded its Six Sigma certificate, based on their accuracy rate, to the dabbawalas (Moore 2011). The Six Sigma improves parts of a system, leading to improvement in the whole organization, with long lasting positive effects for customers and the organization (Benner 2014). Dabbawalas take the same routes every day. These routes are taken both to deliver and return the tiffin. There are no time windows, because the tiffin is always transported at the same time. All tiffins have the same shape and attributes, so that there are no constraints from the product side. They are delivered at the same time, with no constrains from customer side. The overall process is highly standardized. The slow growth of the organization created a good environment for the establishment of a well-functioning routing system. The numerical example comprises the following steps: identification of distance matrix identification of savings matrix assignment of customers to routes and vehicles (i.e., CVRP). The base of the numerical computation with the customers location and demand is shown in Figure 5. These coordinates and order sizes are represented in the following map (Fig. 5). The point of origin is the train station, from where the dabbawala delivers

Question: By assuming a dabbawala can carry a maximum of 14 tiffins on his bicycle, find a solution to the case how should the dabbawalas deliver the tiffins?

- Netail Subhash Chandra Bose Rd PORT TRUST Karve Ad PD Mel 11 LAD WADI Crawford Market 10 LOHAR CHAWL SONAPUR+ Marine Lines PAK WADI Mumbai NAV SVAN Chhatrapati VLADI Sheva DHOBI TALAO Terminus MARINELINES 1 4 GR Marg 2 5 DOCKS Azad Mardan NEW MARINE INES 5 Bombay Hospital Indira Dock Wankhede Stadium 4 3 3 8 2 15 3 D -3 2-1 4 5 6 PAligARD STAV 11 12 st st++ ARd 22 CHURCH 13 Cathedral Church Order Size Number of Customer 1 2 3 NE+ St Thomas Singh Mahatma Do UBAY Figure 5: Location and order size of customers The distance matrix for the dabbawala case study is shown in Table 5 below. Table 5: Distance matrix Station Cust. 1 Cust. 2 Cust. 3 Cust. 4 Cust. 5 0,00 6,40 0,00 Station Customer 1 Customer 2 Customer 3 8,94 4,12 0,00 9,49 5,39 1.41 0,00 5,39 3,16 3,61 4,12 0,00 Customer 4 Customer 5 6,08 4,47 3,61 3,61 1,41 0,00 - Netail Subhash Chandra Bose Rd PORT TRUST Karve Ad PD Mel 11 LAD WADI Crawford Market 10 LOHAR CHAWL SONAPUR+ Marine Lines PAK WADI Mumbai NAV SVAN Chhatrapati VLADI Sheva DHOBI TALAO Terminus MARINELINES 1 4 GR Marg 2 5 DOCKS Azad Mardan NEW MARINE INES 5 Bombay Hospital Indira Dock Wankhede Stadium 4 3 3 8 2 15 3 D -3 2-1 4 5 6 PAligARD STAV 11 12 st st++ ARd 22 CHURCH 13 Cathedral Church Order Size Number of Customer 1 2 3 NE+ St Thomas Singh Mahatma Do UBAY Figure 5: Location and order size of customers The distance matrix for the dabbawala case study is shown in Table 5 below. Table 5: Distance matrix Station Cust. 1 Cust. 2 Cust. 3 Cust. 4 Cust. 5 0,00 6,40 0,00 Station Customer 1 Customer 2 Customer 3 8,94 4,12 0,00 9,49 5,39 1.41 0,00 5,39 3,16 3,61 4,12 0,00 Customer 4 Customer 5 6,08 4,47 3,61 3,61 1,41 0,00