Visiting Santa's Workshop

Visiting Santa's Workshop. Inspired by a local event, this model shows the tractor-trailer ride that brings visitors to Santa's Workshop, a local nature trail with lights and activities. The operation has specified that the two tractors MUST be going the same way down the trail (the trail is only wide enough for one), and they must go simultaneously. How many people can you get through in 4 hours? What does the wait time look like?

0. This model has three items: Visitor, Tractor, and Full Tractor (made up of 1 Tractor and 15 visitors) 

1. Model the arrival rate of Visitors. Set the distribution of time as people arrive.

2. Wait for a Group to arrive before reading the rules. As visitors gather around the elf to hear the rules, the elf won't start until at least six people are together, but they also can't talk to more than 20 at one time (or participants won't be able to hear).

3. Unbatch all in this Queue. After Visitors listen to the elf, it's time to wait for the Tractor.

4. Set the Initial Tractors. Add Tractor as an item in this Queue and set the Initial on Hand to 2. This action will ensure we have two tractors along the trail.

5. Ensure only one Tractor can be loaded at a time. This Core Pull block envelopes the Move Stairs, Unload, Load, and Move Stairs Away activities. This will prevent the second tractor from being loaded while the first one is in the way.

6. Combine the Tractor with the Visitors in a Kit Block. Reality would tell you to put this block closer to the Load People block; however, in this case, we care more about the usage of the Truck than being precisely accurate with wait times for the Visitors. We're willing to accept a rougher estimate on Visitor's time to be accurate with the Tractor's time.

7. Wait for the other Tractor with a Batch Block. This block is set to create a batch with a minimum of 2 and a maximum of 2. This means as soon as both tractors are full, then the batch will release. 

8. Unbatch the Tractors. This ensures that we will work on each one separately.

9. Drive the Tractors down the road. This Activity block has two Servers, which means both tractors can go down the road at the same time. 

10. Split the Visitors from the Truck here. Reality strikes again where you might be interested in putting this split after Unload. However, since we care more about the Tractor usage, we will split the individuals off here, recognize they'll be waiting some time for the stairs and unloading, and call it a day. 

11. Repeat the process, going back the other way. Since some of the time is spent with visitors returning, let's model the same process going in the other direction.

This model highlights the use of the batch block, blocking items from moving forward until there are enough to move on to the next step. This model also highlights the importance of understanding the problem you want to solve with your model to best match the model to real life.