A very large part of the information contained in this blog is translated from the French.
Jose Banaudo is the author of the book written in French about the tramways of Nice and the Cote d’Azur.  I have translated the part of that book which refers to the Great War with the help of internet-based translation software and report on it here, supplemented with additional information where available.
World War 1
In the fifteen years prior to the Great War, the growth of the population of Nice and the surrounding towns and villages necessitated a rapid development of the tram network. The advent of the Great War prevented any further significant development of the network and by the end of the war, the network was in need of an in-depth modernization programme. However, it was not until 1924 that the authorities granted the TNL the authorization to increase tariffs.
During the War, a number of small schemes were undertaken with military needs in mind. Among other things, the network managed to obtain a connection to the PLM at the Saint Roch station and a connection with the Cannes tramways in the streets of Antibes. 
Traffic decreased during the War, especially that of tourists. The condition of the tracks deteriorated, especially on the Monte Carlo line. Plans were made to modify some curves in order to admit bogie engines on the line, with the restoration of a few sections of track. This work was completed on 3rd September 1918.
Trams Serving the War Economy
The TNL was called upon to undertake a very important role in the national war effort and in supplying the region. As Nice was in a border zone, the arrangements for making tramways available to the military authority “in the event of a mobilisation, alert or unexpected attack” were established on 14 January 1910 by an agreement between the authorities in Nice, the TNL and the EELM company which was in charge of ensuring the electricity supply to the network.
From the date of the mobilisation, all the rolling stock assigned to the transport of goods (i.e. twelve tractors and one hundred and forty wagons) was made available to military. Within three days. 2110m of tracks were laid to connect the military establishments in the Riquier, St. Roch and Bon-Voyage districts, east of Nice, to the tramway network, to barracks, handling yards, subsistence shops and forage yards. Stables were set up at the Var racecourse in St. Augustin, and a military training camp was created in the St. Véran district at the exit of Cagnes.
The tramways transported nearly a thousand tons of food, military equipment and materials, ammunition and medicines, horses, mules, straw and fodder. Some of the supplies were unloaded at the port, often from the colonies. Other supplies arrived in Nice by the PLM, whose wagons were transferred along a street connection to a transhipment platform in La Gare du Sud where a company of territorials, relieved every three hours, ensured day and night the transhipment onto the wagons of the TNL.
In the months following mobilisation, military demands gave way in part to the needs of civil life: coal for the gas plant, wheat for the flour mills, goods for other French regions and even for Switzerland, etc.
La Gare du Sud was heavily congested. In order to relieve that pressure and accelerate the transshipment of goods, the TNL, the PLM and the Chamber of Commerce concluded an agreement in March 1915, to establish a connection between the tramway to Contes and the new station at Nice-St. Roch, where a series of sidings were created to facilitate transshipment. This installation, had a capacity of a thousand tonnes per day, was made operational in July.
The tramway workshop at boulevard Sainte-Agathe was one of the best industrial establishments of the city of Nice, and the military authorities took it over in January 1915 and conferred on the TNL the responsibilty for machining 75 mm shell blanks and training some 30 small businesses in the region to do this type of work. Manufacturing subsequently extended to 120 mm shells and small bombs. These small bombs were intended to be dropped by hand from aeroplanes. The raw materials were transported by railway from the Toulon arsenal to Nice, and the finished items were transferred in the opposite direction. Congestion on the PLM coastal line eventually led to these exchanges being undertaken by sea.
The depot of Sainte-Agathe also converted wagons required on the other networks for by the military field railway.
The year 1917 saw tramway traffic increase in several areas. On 26th March 1917, a daily coal train was put into operation from the port of Nice to the gas plant of Cannes, located near Mandelieu. From 17th November 1917 an additional service transporting cement from Contes to Mandelieu for the construction of the new military camp at Fréjus was commissioned. When the cement arrived at the end of the Cannes network, cement was transshipped by trucks.
Transport of the wounded.
From the first months of the conflict, most of the large hotels in the towns and cities of the Côte d’Azur had been requisitioned to house wounded and convalescing soldiers, war orphans and civilian refugees from the evacuated areas. The lines of the urban network of Nice as well as those of the coast which served these establishments experienced an intense traffic, increased from 1917 by contingents of Americans.
The most seriously injured soldiers had to travel lying down. During the summer months, sixteen modified open trailers were used to carry 10 stretchers. During the cold season, a tractor and eight vans were fitted out to accommodate 12 stretchers on three levels. If necessary, eight conventional urban power cars could each carry 8 stretchers.
There were twenty-eight hospitals in the city of Nice and its surroundings, these included the two mixed civilian and military hospitals of St. Roch and Villefranche, six auxiliary hospitals, ten additional hospitals, seven hospitals managed by volunteer staff and three convalescent centres, most of which were set up in requisitioned villas, residences and hotels.
There are some excellent images showing the hospital trams in Banaudo’s book.
- Jose Banuado, Nice au fil du Tram, Volume 1; Les Editions du Cabri, 2004.
- http://transporturbain.canalblog.com/pages/les-tramways-de-nice—de-l-apogee-au-declin/31975780.html, accessed on 24rh August 2018.