Waiting for water

The tower at five moments, on one scale

All the bars share the same scale, 0 to 30,000 l. The red mark shows how much water the tower must hold for the tender to take a full load without help from the pump. When a bar does not reach it and the pump is stopped during the stop, water runs short.

1. Model start (assumed)10,000 l
2. After preparation: 20 min of pumping18,000 l
3. After the stop of locomotive A10,000 l
4. Before B arrives: 10 min gap14,000 l
5. After the stop of locomotive B0 l

The red mark at moment 2: 8,000 l, the amount tender A needs. At moment 4: 15,000 l, the amount tender B needs.

Tenders after the stop, scale 0 to 18,000 l

1. Tender A (capacity 12,000 l)12,000 / 12,000 l
2. Tender B (capacity 18,000 l)17,000 / 18,000 l

Grey section: the water the tender had at the start (A 4,000 l, B 3,000 l, assumed). Blue: taken from the crane. Red dashed: missing to full. Black line: tender capacity.

Stop time: A 8.0 min, B 14.0 min (until the water runs out).

Tower balance: start 10,000 l + from the pump 12,000 l − given to A 8,000 l − given to B 14,000 l = 0 l at the end.

Why a tower? If the crane drew directly from the pump (400 l/min), filling A would take 20.0 min and B 37.5 min. With the tower: A 8.0 min, B 14.0 min (until the water runs out).

Units: litres (l), minutes (min). The numbers are model assumptions, rounded to a whole litre for display.

TO BE CHECKED AT THE SOURCE · description carried over from V2, not reopened in V3

Chabówka: the water crane is only the middle of the story

According to the open-air museum's description, two water cranes have survived in Chabówka; they supplied locomotives and also filled the tanks of railway carriages. The model above describes a layout with a tower. The museum's description, however, says that this layout changed over time in Chabówka, so this page does not reproduce the installation as it is today.

We do not know from the material on this page exactly how each of the cranes is supplied today, or what their real capacities are. That is why the numbers in the model are assumed.

Safety limit. The water cranes stand beside active or museum tracks. Do not climb on the structure, do not operate a valve without the staff's consent and do not enter the loading gauge of the track. This page is not an operating manual for a water crane.

Limits of the model and what was removed from V2

The model calculates minute by minute: the pump tops up the tower (up to its capacity), and the crane gives the tender at most what the tender needs, what fits within the crane's limit and what is in the tower. The stop ends when the tender is full or when there is no water left in the tower and the pump is not running.

PUMP

400 l/min (assumed)

WATER CRANE, MAXIMUM

1,000 l/min (assumed)

TOWER

capacity 30,000 l, start 10,000 l (assumed)

TENDER A

12,000 l, start 4,000 l (assumed)

TENDER B

18,000 l, start 3,000 l (assumed)

PRESSURE AND LEVEL

not modelled; the line does not mean an equal water level in the tanks

We do not know: exactly which water layout and supply is meant to be shown (to be confirmed with the museum), how long real stops lasted, or what the real capacities were. A tower start of 10,000 l with the default 20 min of preparation gives 18,000 l, which is the initial value from V2.

What was removed from V2 and what replaced it

• Choice of locomotive A/B: both locomotives are now successive scenes of a single sequence, because the state of the tower after the first stop matters.
• Valve 0 to 100% and arm position: in V2 the valve mainly changed the rate and time of filling (with the pump on, also how much water the pump managed to add during the stop), while the arm only cut off the draw. V3 fixes them at full opening and the working position, and shows the effect of the pump during the stop with a switch. The detail stays in the second layer, that is, in the description of the model.
• Time steps of 1 min and 5 min: replaced by a scene that shows the state at the end of a phase, and by the stop time given beside it.
• The “To full” calculator and the session table: they repeated the result visible at the tender. Replaced by two rows of tenders and a message under the controls.
• Form for custom parameters: abandoned. The parameters are fixed and listed above, so that the result does not depend on fields that explain nothing.
• Embedded photograph from Wikimedia Commons: the page does not load external resources, so only the link with attribution remains in the sources.

Kept from V2: the balance logic (pump inflow limited by the tower's capacity, outflow limited by the tender's need, the crane's limit and the tower's stock), the values 400 l/min, 1,000 l/min, 30,000 l, tenders of 12,000 l and 18,000 l and the initial states of 4,000 l and 3,000 l, the references to sources and the safety limit.

What was not checked in this version: whether the target catalogue pages, V1 and V2 exist, and whether the links work after deployment (the integrator checks this), as well as the content of the external sources.