There is a system consisting of:
$\mathbf{Workcentres:}$
6 workcentres $W_i$ assumed to be operating at different rates $\mu_{W_i}$, which depends on which input is being worked on. Assume there are at most $50$ inputs that can feed into each workcentres stated below
Each $W_i$ is feeded work from 1 input queue $Q_{input_i}$
$W_1$ does work twice on an input - first to a holding queue $Q_H$, then is worked on again, then it goes to an output queue - call it $Q_{Output1}$.
All other $W_i$ feed their output into one of two queues $Q_{OutputL}$, and $Q_{OutputS}$ - one for large items, and another for small items.
$W_2$ can take some, but not all of the same input work as $W_1$.
When a $W_i$ needs work but there is no work for it the $W_i$ sits idle.
Any of the $W_i$ can break down.
$\mathbf{People}$ $\mathbf{P_j:}$
There are assumed to be up to $5$ people $P_j$ available at one time in the system that can man the $W_i$.
Only $1$ $P_j$ is needed per $W_i$ when at the workcentres to make the output.
Each $P_j$ moves around between a $RestArea$, all relevant queues, the workcentres, inside storage $R_k$ outside storage $R_{Storage}$ for the work required to be done - this is via vehicle or walking.
All $P_j$ can stop at the $RestArea$ up to 2 times a day for upto 30 minutes on each occasion.
Walking speed for each $P_j$ between points a and b is $T_{Pab}$ and is between $3$ and $6$ mph.
A $P_j$ cannot man more than one workcentre $W_i$.
$P_j$ move onto the next work in input queue once output they are working on is in an output queue, unless they go on to the $RestArea$ for a break.
Infrequently (eg once per day) a spillage occurs. This means if the $P_j$ is manning a $W_i$ at the time, production on that $W_i$ is halted, while the $P_j$ mop the spillage. This takes an average (mean) of 5 mins. Then the $W_i$ is manned again, and work continues.
$\mathbf{Queues:}$
Work arriving in the input queues are not turned away, and sits there until worked on by workcentres.
Output in the output queues sits there until collected (demand driven). Assume that output queues have unlimited capacity.
Input into $Q_{input_i}$ is demand driven by what work is needed. Input is assumed to arrive by person via walking.
$\mathbf{Resources}$ $\mathbf{and}$ $\mathbf{vehicles:}$
Each workcentre $W_i$ needs a a set amount of Resources. There are resources in two locations inside: $R_1$, $R_2$.
If one or more resources in any $R_k$ is not available for a workcentre $W_i$, then the input sits in that input queue.
All of the resources needed from the $R_k$ to each $W_i$ and back are moved by vehicle $V_l$.
There is a storage area outside where more resources are kept - call it $R_{storage}$. Resources are fetched from here by a $V_l$ if not in any of the $R_k$. Resources can be placed back in $R_{Storage}$ when there is no space left in any of the $R_k$.
There are assumed to be infinite $V_l$ available, have a maximum speed $V_{max}=20$mph, and time $T_{Vab}$ from $a$ to each destination $b$ is a function depending on which $P_j$ is driving it.
Only $W_3$, $W_4$ and $W_5$ need resources, thus vehicles do not go to $W_1$, $W_2$, and $W_6$.
$\mathbf{Output}$ $\mathbf{work}$ $\mathbf{and}$ $\mathbf{collectors}$ $\mathbf{D_m:}$
Output work can be rejected upstream and infrequently arrives back randomly into the system back as different input (same amount in as out) by person.
Output is assumed to exit system via either of two pedestrian doors by person, $D_m$. $1$ $D_m$ arrives to collect some of the output in the applicable queue every $8$ hours.
It is assumed that there is always at least $1$ $D_m$ available for checking the output queues.
Walking speed for each $D_m$ between points a and b is $T_{Dab}$ and is between $3$ and $6$ mph.
$\mathbf{Distances}$ $\mathbf{and}$ $\mathbf{area:}$
All positions of the $W_i$, $R_k$, $R_{Storage}$, queues and $RestArea$ are assumed to be at least 2metres apart, and are within 20metres of each other.
The dimensions of the area are estimated to be 100metres length by 60metres width.
In the diagram of the system below:
The $V_l$ (with 1 $P_j$ driving) can only go on blue paths.
The $P_j$ when they are walking can go on the Black or Red paths.
The $D_m$ can only go on the Red paths.
$\mathbf{Diagram:}$
https://i.stack.imgur.com/LtQah.jpg
1) What models I should be using for modelling each part of this system ($W_i$, $R_k$, $RestArea$, all the input, output and holding queues, $P_j$, $V_l$, and $D_m$) in its current form?
2) Somes names of free simulation software that can model this system (eg Simio has a limit of 30 objects which is insufficient)?
I intend to update this question as and when needed to clarify any questions / points in comments.