## 3 Methodology
### Discussion  
(1) Comparison of whether or not to consider coal storage and distribution bases  
This section compares the solutions with and without coal storage and distribution bases, where the distribution solution without coal storage and distribution bases is the traditional solution of coal storage and logistics. This section of the transfer cycle for two days under the integrated transport system of public-railway coal transport research considers transfer optimization to determine whether to take into account the storage and distribution of coal base inventory factors. Using the gurobi solution to obtain the coal transfer scheme, at the coal consumption place of Beijing (node 6), with a direct sale, there is no inventory. At the Dingzhou power plant (node 11) and the China Resources Group coal chemical plant (node 13), there is a steady rate of coal consumption during production and processing. The source of coal consumption is coal stockpiles and coal transported in the \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Coal** & **Departure** & **Arrival Time** & **Transport** & **Type of** & **Transmit** & **Transit Time** & **Storage** & **Cost** & **Volume of** \\
**Batches** & **Time** & **Routes** & **Transport** & **Node** & **Time** & **Time** & **Freight** \\ \hline
1 & 10:00 & 15:15 & 3-7-8-0-11-1 & Railway & - & - & - & 244,077 & 5000 \\
2 & 8:00 & 14:30 & 7-8-9-10-12-1 & Railway & - & - & - & 293,376 & 5000 \\
3 & 16:45 & 24:00 & 14:15 & Railway & - & - & - & 588,800 & 10,000 \\
4 & 2 nd day, 7:15 & 2 nd day, 8:00 & 15-11 & Freeway & 15 & 24:00–2 nd day, & 2 nd day, 4:00–2 nd & 35,760 & 2000 \\
5 & 2 nd day, 2 nd day, & 13:15 & 14:00 & 15-11 & Freeway & 15 & 24:00–2 nd day, & 2 nd day, 4:00–2 nd & 36,240 & 2000 \\
6 & 2 nd day, 4:15 & 2 nd day, 5:00 & 15-13 & Freeway & 15 & 24:00–2 nd day, & 4:00–2 nd day, & 57,000 & 3000 \\
7 & 2 nd day, 2 nd day, & 11:15 & 12:00 & 15-13 & Freeway & 15 & 24:00–2 nd day, & 2 nd day, 4:00–2 nd & 57,870 & 3000 \\
8 & 2 nd day, 2 nd day, & 2 nd day, & & & & 4.00 & day, 11:15 & 57,870 & 3000 \\
11:15 & 14:00 & 5-6-12-14-13 & Railway & - & - & - & - & 751,660 & 10,000 \\
9 & 2 nd day, 2 nd day, & & & & & 2 nd day, & 2 nd day, & \\
10 & 3 rd day, 1:15 & 3 rd day, 2:00 & 15-11 & Freeway & 15 & 14:00–2 nd day, & 18:00–2 nd day, & 35,600 & 2000 \\  & & & & & & 18:00 & 19:15 & & \\  & & & & & & 2 nd day, & 2 nd day, & & \\
11 & 2 nd day, & 2 nd day, & & & 14:00–2 nd day, & 18:00–3 rd day, & 36,080 & 2000 \\  & & & & & & 18:00 & 1:15 & & \\  & & & & & & 2 nd day, & & 2 nd day, & \\  & & & & & 14:00–2 nd day, & - & 57,000 & 3000 \\
12 & 2 nd day, & & & & & 18:00 & & \\
13 & 16:30 & 18:30 & 5-6 & Railway & - & - & - & 223,079 & 5000 \\
14 & 12:75 & 18:30 & 3-4-5-6 & Railway & - & - & - & 217,525 & 3000 \\
15 & 2 nd day, & & & & & & & 234,745 & 3000 \\
16 & 2 nd day, 6:15 & 11:30 & 3-4-5-6 & Railway & - & - & - & 222,879 & 5000 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Demand for coal where coal is consumed. previous time period, and the coal outflow is the production of coal for consumption and the remaining part of the savings for the stockpile. Therefore, this section only considers the comparison of the stockpiles transported to the Dingzhou power plant (node 11) and the CRG coal chemical plant (node 13). A comparison of the different parts of the two transfer schemes is shown in Table 6.  
In terms of the transfer program, without considering the role of the storage and distribution base in transit storage, coal needs to be loaded and shipped from the coal source to the coal consumption place. With a longer transport time, each time the amount of inventory change is the amount of coal shipped for that batch, there is a higher cost of inventory at the coal consumption place.