Tests of train brakes are called the technological operations through which the serviceability of the train’s automatic brakes is checked and established.
Each test starts and ends with the automatic brake fully loaded and released.
The brake must be pressurized:
a) In the main air duct for electric motor trains series 32.00 – with 5.5 bar;
b) In the main air duct for the other trains – with 5.0 bar;
c) In the main air tanks of the traction rolling stock or stationary air station installations – not less than 6.5 bar.
The following tests are performed on automatic brakes:
- Sample A (full sample);
- Sample B (partial sample);
- Sample D (abbreviated sample);
- Warm sample.
Sample A is performed:
- of all trains at the starting station for their movement;
- on all motor trains before leaving a depot or equipment station (in this case, no sample A is carried out at the starting station, and the brake mass certificate is issued for the first serviced train and is valid for all serviced trains until the end of the day or until the arrival of the last serviced train at the final station);
- of freight trains that have undergone a change in their composition without carrying out sample A of the entire train, which are due to travel on a long and long descent from profile stations that are determined by the manager of the railway infrastructure with the rules under Art. 7, para. 1.
- of the wagons that start from an intermediate station, but not earlier than 30 min before the train’s arrival;
- in the case of a dropped train, when passing a closed traffic light, closing the front distance and at the request of the driver, when there is doubt as to whether the train is equipped with a brake mass;
- when the train is stationary for more than one hour and the outside temperature is equal to or lower than minus 10 °C (for this purpose, there must be a thermometer for measuring the outside temperature in each operational station);
- when changing the modes of the automatic train brake. Test A of the brakes of one train is allowed to be carried out in two parts as well. After connecting them, a D sample is performed on the entire train.
Sample B is performed:
- of a train set, on which sample A has been made in advance and the train locomotive was attached after more than 120 min. after the end of the sample (after sample B is performed, sample D is also made);
- when a formation maneuver is performed after the completion of Sample A;
- when the train departs after the end of the duty of the test taker A;
- when taking away a train that has not undergone a change in its composition and has been at a station for more than 60 minutes without a locomotive or with a locomotive in an inactive state;
- on a wagon with a forced brake release via the release valve.
- at any violation of the integrity of the train’s main air duct;
- when a train departs from profile stations, from which a large descent begins, determined by the manager of the railway infrastructure;
- when attaching the train locomotive to a train on which sample A was previously taken;
- when coupling and uncoupling an auxiliary locomotive in the lead and when coupling an auxiliary locomotive as a pusher;
- before the departure of a train after a stay of more than 20 min. without changing the composition from a station or from an intermediate station (if it is impossible to perform sample D at an intermediate station, the same is performed at the first en route station);
- when changing the train locomotive or the command consoles of locomotives or motor trains;
- when changing the locomotive brigade;
- after joining the parts of a train on which sample A has previously been carried out;
- on all categories of passenger trains from the starting station, served by motor trains;
- of all categories of passenger trains that do not change their composition and after staying at intermediate or terminal stations for up to 60 minutes continue their movement in the same, reverse or other direction under other numbers.
On locomotives with computerized testing and control of the braking system in train service alone or in a multi-unit system, sample D is not carried out.
Sample D
The purpose of the abbreviated sample or D sample is to check the integrity and passability of the train’s GWP from the crane driver to the last car and back and that the automatic brake is engaged and working.
An abbreviated sample is performed as follows:
1. Blow the DHW from the tap on the last car of the train until clean and dry air starts to come out.
2. The tester stands next to the last car and gives a signal to release the automatic brake. After making sure that the brake on the last car is released, he gives a signal to hold the brake.
3. The driver makes a gradual stop by reducing the pressure in the GVP by 0.5 – 0.7 bar (0.8 – 0.9 bar, for trains in which wagons with composite blocks are included).
4. The test taker checks whether the brake of the last car has held. After confirming that the brake of the last car has been applied, the test taker gives a signal to release the brake.
5. The locomotive driver releases the brake, the tester checks whether the brake of the last car is released, and if this condition is met, he signals the end of the test.
Warm sample
The hot test is a way to establish the effectiveness of the serviced brakes of the train, by determining the degree of heating of the “pad-wheel” or “brake disc-pad” friction assemblies.
Warm sample is performed:
- in the event of a missed train;
- when passing a closed traffic light by a train that has been moving downhill for a long time in braking mode for speed regulation;
- with a closed front distance from a train that has been moving downhill for a long time in braking mode for speed regulation when entering a station;
- at the request of the locomotive driver.
Locomotive drivers of all categories of trains must carry out a train brake efficiency check:
- when a train departs from initial or profile stations determined by the manager of the railway infrastructure;
- when the train is running at a temperature lower than – 10 °С, and the automatic train brake has not been used for more than 30 min.
On passenger and mixed trains, a check of the effectiveness of the automatic train brake is carried out after the carriages have left the platforms or passenger boarding places.
Handbrake test
Hand brakes are mechanical devices that, depending on the construction scheme of the lever brake system, ensure the braking of all wheel axles or a part of the wheel axles of the rolling stock.
It is allowed to use the hand brakes of freight wagons to stop working, shunting and special trains.
When using the hand brakes, the turning devices of the wagons are set to “loaded wagon” mode, regardless of whether the wagon is empty or loaded.
Vebeo Review, about fittings.