BS EN 15612 pdf free download
BS EN 15612 pdf free download. Railway applications – Braking – Brake pipe accelerator.
4 Design and manufacture
4.1 General
The design and manufacture of the brake pipe accelerators shall comply with this document.
4.2 Functional requirements
4.2.1 General
Brake pipe accelerators shall be able to operate with all distributors valves that conform with EN 15355:2019 and all existing brake pipe accelerators that comply with the requirements of this document.
The brake pipe accelerator shall be ready to operate when the brake pipe has reached the normal working pressure. The brake pipe accelerator shall operate in response to a defined rapid fall of brake pipe pressure to ensure a continuing rapid fall to below 2,5 bar.
4.2.2 Operating requirements
The following operating requirements are defined in relation to the normal working pressure of (5,00 ± 0,05) bar. When an emergency braking occurs, the brake pipe accelerators shall create a sufficiently rapid reduction in brake pipe pressure to ensure the rapid increase in brake cylinder pressure on every vehicle in the train set. When the pressure in the brake pipe has fallen quickly to below 2,5 bar, and within no more than 4 s after the brake pipe accelerator commences operation, the brake pipe accelerator shall stop venting air so that the brake pipe can rapidly be refilled. This requirement shall be proven by testing in accordance with 5.2.4.4.
No functional errors shall occur in the operation of the brake pipe accelerator at input pressures of (5,00 ± 1,00) bar. This requirement shall be proven by testing in accordance with 5.2.4.10.
4.2.3 Train behaviour
The brake pipe accelerator shall exhaust the air from the brake pipe without causing any adverse effect on train behaviour. This requirement shall be proven by testing in accordance with 5.3.
4.2.4 Effect of overcharge
4.2.4.1 Overcharge after full service braking
The brake pipe accelerator shall not come into operation due to the effect of a normal working pressure overcharge after a full service braking, which allows a build-up of brake pipe pressure above normal working pressure to 6,00 bar. It shall be taken into account that this overcharge can be present for up to 40 s in brake mode “G” and 10 s in brake mode “P” after a full service braking. This requirement shall be proven by testing in accordance with 5.2.4.8.
4.2.4.2 Overcharge starting from normal working pressure
The brake pipe accelerator shall not come into operation if the brake pipe pressure, starting from the normal working pressure, is raised to 6,0 bar for 2 s, then is reduced to 5,2 bar in 1 s, followed by a return to the normal working pressure at a rate of 0,15 bar in 60 s. This requirement shall be proven by testing in accordance with 5.2.4.9.
4.2.5 Effect of individual vehicle The operation of the brake pipe accelerator shall not be aftected by an individual vehicle with a brake pipe volume not exceeding 25 1, where a brake pipe accelerator is not fitted or the brake has been isolated. This shall apply irrespective of the position of that vehicle in the train consist. This requirement shall be proven by testing in accordance with 5.3. 4.2.6 Subsequent emergency braking The brake pipe accelerator shall come into operation when an emergency braking is applied after a full service braking. This requirement shall be proven by testing in accordance with 5.2.4.7. 4.2.7 Sensitivity The brake pipe accelerator shall come into operation as response to a drop in brake pipe pressure with a gradient of 1,80 bar in (3,0 + 0,1) s starting from input pressure of (5,00 ± 0,05) bar with a maximum delay of 2 s. This requirement shall be proven by testing in accordance with 5.2.4.4. 4.2.8 Insensitivity to brake pipe pressure fall The brake pipe accelerator shall not come into operation as response to a drop in brake pipe pressure with a gradient of 1,80 bar in (6,0 + 0,3) s starting from input pressure of (5,00 ± 0,0 5) bar. Continuing the pressure fall down to 2,5 bar shall not cause the brake pipe accelerator to operate. This requirement shall be proven by testing in accordance with 5.2.4.5.BS EN 15612 pdf download.
