Drawing of the gantry crane - continued

Cab

The cab shown on this photo, which I want to reproduce, differs from the one of the diagram: it has sloping sides down to improve the visibility of the driver.

Click the following colours to highlight the corresponding item.

Blue: front railing
Green: rear railing
Violet: ladder
Red: rear grille.

Photo of cab

At the level of the ladder giving access to the upper walking platforms, there are safety grilles whose position and fixing are not obvious. So I’ll have to make assumptions while trying to stick closer to reality.

Click the following colours to highlight the corresponding item.

Blue: front railing
Green: rear railing
Violet: ladder
Red: rear grille.

Photo of cab access

So here is my interpretation of this cab and the associated guardrails. The gantry crane leg is left in “wire” to allow to see the hidden parts. The pieces are obviously in false colours. The cabin windows are made of transparent ep. 0.25 (at 1:87) material. The high and narrow grille above the rear guardrail (highlighted in red on the photos) has not been shown yet, as I do not see how it is fixed. The colour conventions are the same as in the previous pictures.

Cab

The rear protection of the ladder appears to be a horizontal bar frame, but it is not possible to know whether the bars are round or rectangular. I opted for the rectangle, easier to weld on the chassis. The superior shape of the latter is at most probable.

Cab access ladder

For the access ladder, I used a 320 mm rung distance and a 470 mm width. There are a total of 24 rungs, one support and one safety hoop every five rungs. The first hoop corresponds to the third support from the bottom. The hoops are connected by heddles, one on each side and one on top, to form what is called a caged ladder. The heddles will be welded to the stairwell opened in the cab access platform.

Photo of access ladder

In the photo of the gantry crane under construction, we see that the lateral heddles are missing. Maybe they had not been originally planned, and were added later to improve safety.

Note: on modern gantries it is recommended to install stairs instead of ladders, with intermediate resting landings.

Progress report

It’s going on… Attention: the ladder must be motor side. To be rectified !

Cab and ladder

Top walking platforms and electric cabinets

Here, I will have to appeal even more to the imagination — while remaining in technical logic — because I have no photos of views from above (except a Google Earth satellite photo of very little detail). Between the two girders is a rather large platform (coloured in red), placed on beams, bearing two electric cabinets, one for lifting, the other for translation and direction movements.

Photo of walking platforms

A walking platform (coloured or framed in green) runs on a small half of the turn of the gantry crane and communicates with the platform previously seen. It is accessible by the ladder located near the cab (framed in blue). However, one cannot distinguish an opening at this place. There is probably an access hatch closed in normal use, for safety reasons.

Other photo of walking platforms

Note: on other photos of newer gantries, the walking platform extends more towards the middle of the girder, in line with the central platform (green dotted lines on the first photo), probably to improve access to the trolleys.

Here is how I imagine these elements. As for the platform guardrail (in front of the cabinets), I assumed it is independent of that of the walking platforms attached to the girders. Indeed, the elements are mounted one after the other; the platform being mounted after the girders, I think it must have an independent guardrail. At this place I have also placed a flange, for it can be seen on all the walking platforms; their role is to prevent objects such as tools from falling. Always safety: a big wrench can do some harm, falling from a height of ten meters…

Plateformes

Progress report

I coloured the new elements in orange to see them a little better in the middle of everything yellow… The cabinets are in gray.

Platform

An observation

In this satellite photo, the cabinets are invisible, protected by a double slope roof, probably in corrugated iron. On the other hand, the visible link between the two trolleys (a white line passing over the cabinet roof) is used to control the offset between these trolleys.

Paris La Chapelle Gantry crane