What's the Difference Between a Bi-level Home and a Split-level Home?

What's the difference between a bi-level home and a split-level home?

Split-level is pretty much just two sections of a two-story home set side-by-side in construction but off-set half-way in height so you actually end up with four separate levels interior accessed by three seperate stairways. The front door can access a level foyer on any level. A Bi-level I think is just a 2-story colonial or a ranch walk-out. A split-foyer is what your front entry way is coming in from the front door

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Levels of ETCS

ETCS is specified at four numbered levels: Level 0: ETCS-compliant locomotives or rolling stock do not interact with lineside equipment, i.e. because missing ETCS compliance. Level NTC (former STM): ETCS-compliant driving cars are equipped with additional Specific Transmission Modules (STM) for interaction with legacy signalling systems. Inside the cabs are standardised ETCS driver interfaces. With Baseline 3 definitions it is called National Train Control. Level 1: ETCS is installed on lineside (possibly superimposed with legacy systems) and on board; spot transmission of data from track to train (and versa) via Eurobalises or Euroloops. Level 2: As level 1, but eurobalises are only used for the exact train position detection. The continuous data transmission via GSM-R with the Radio Block Center (RBC) give the required signalling Information to the drivers display. There is further lineside equipment needed, i.e. for train integrity detection. Level 3: As level 2, but train location and train integrity supervision no longer rely on trackside equipment such as track circuits or axle counters.Level 0Level 0 applies when an ETCS-fitted vehicle is used on a non-ETCS route. The trainborne equipment monitors the maximum speed of that type of train. The train driver observes the trackside signals. Since signals can have different meanings on different railways, this level places additional requirements on drivers' training. If the train has left a higher-level ETCS, it might be limited in speed globally by the last balises encountered. Level 1Level 1 is a cab signalling system that can be superimposed on the existing signalling system, leaving the fixed signalling system (national signalling and track-release system) in place. Eurobalise radio beacons pick up signal aspects from the trackside signals via signal adapters and telegram coders (Lineside Electronics Unit - LEU) and transmit them to the vehicle as a movement authority together with route data at fixed points. The on-board computer continuously monitors and calculates the maximum speed and the braking curve from these data. Because of the spot transmission of data, the train must travel over the Eurobalise beacon to obtain the next movement authority. In order for a stopped train to be able to move (when the train is not stopped exactly over a balise), there are optical signals that show permission to proceed. With the installation of additional Eurobalises ("infill balises") or a EuroLoop between the distant signal and main signal, the new proceed aspect is transmitted continuously. The EuroLoop is an extension of the Eurobalise over a particular distance that basically allows data to be transmitted continuously to the vehicle over cables emitting electromagnetic waves. A radio version of the EuroLoop is also possible. For example, in Norway and Sweden the meanings of single green and double green are contradictory. Drivers have to know the difference (already with traditional systems) to drive beyond the national borders safely. In Sweden, the ETCS Level 1 list of signal aspects are not fully included in the traditional list, so there is a special marking saying that such signals have slightly different meanings. Limited SupervisionWhereas ETCS L1 Full Supervision requires supervision to be provided at every signal, ETCS L1 Limited Supervision allows for only a part of the signals to be included, thus allowing to tailor the installation of equipment, only to points of the network where the increase in functionality justifies the costs. Formally, this is possible for all ETCS levels, but it is currently only applied with Level 1. As supervision is not provided at every signal, this implies that cab signalling is not available and the driver must still look out for trackside signals. For this reason, the level of safety is not as high, as not all signals are included and there is still reliance on the driver seeing and respecting the trackside signalling. Studies have shown that ETCS L1 LS has the same capacity as plain Level 1 FS for half the cost. Cost advantages come from reduced efforts necessary for calibrating, configurating and designing the track equipment and ETCS telegramms. Another advantage is, that Limited Supervision has little requirements for the underlying interlocking, hence it can be applied even on lines with mechanical interlockings as long as LEUs can read respective signal aspects. In contrast Level 2 requires to replace older interlockings with electronic or digital interlockings. That has led to railway operators pushing for the inclusion of Limited Supervision into the ETCS Baseline 3. Although interoperable according to TSI, implementations of Limited Supervision are much more diverse than other ECTS modes, e.g. functionality of L1LS in Germany is strongly based on PZB principles of operation and common signal distances. Limited Supervision mode was proposed by RFF/SNCF (France) based on a proposal by SBB (Switzerland). Several years later a steering group was announced in spring 2004. After the UIC workshop on 30 June 2004 it was agreed that UIC should produce a FRS document as the first step. The resulting proposal was distributed to the eight administrations that were identified: ÖBB (Austria), SNCB/NMBS (Belgium), BDK (Denmark), DB Netze (Germany), RFI (Italy), CFR (Romania), Network Rail (UK) and SBB (Switzerland). After 2004 German Deutsche Bahn took over the responsibility for the change request. In Switzerland the Federal Office of Transport (BAV) announced in August 2011 that beginning with 2018 the Eurobalise-based EuroZUB/EuroSignum signalling will be switched to Level 1 Limited Supervision. High-speed lines are already using ETCS Level 2. The north-south corridor should be switched to ETCS by 2015 according to international contracts regarding the TEN-T Corridor-A from Rotterdam to Genova (European backbone). But it is delayed and will be usable with December 2017 timetable change. Level 2Level 2 is a digital radio-based system. Movement authority and other signal aspects are displayed in the cab for the driver. Apart from a few indicator panels, it is therefore possible to dispense with trackside signalling. However, the train detection and the train integrity supervision still remain in place at the trackside. Train movements are monitored continually by the radio block centre using this trackside-derived information. The movement authority is transmitted to the vehicle continuously via GSM-R or GPRS together with speed information and route data. The Eurobalises are used at this level as passive positioning beacons or "electronic milestones". Between two positioning beacons, the train determines its position via sensors (axle transducers, accelerometer and radar). The positioning beacons are used in this case as reference points for correcting distance measurement errors. The on-board computer continuously monitors the transferred data and the maximum permissible speed. Level 3With Level 3, ETCS goes beyond pure train protection functionality with the implementation of full radio-based train spacing. Fixed train detection devices (GFM) are no longer required. As with Level 2, trains find their position themselves by means of positioning beacons and via sensors (axle transducers, accelerometer and radar) and must also be capable of determining train integrity on board to the very highest degree of reliability. By transmitting the positioning signal to the radio block centre, it is always possible to determine that point on the route the train has safely cleared. The following train can already be granted another movement authority up to this point. The route is thus no longer cleared in fixed track sections. In this respect, Level 3 departs from classic operation with fixed intervals: given sufficiently short positioning intervals, continuous line-clear authorisation is achieved and train headways come close to the principle of operation with absolute braking distance spacing ("moving block"). Level 3 uses radio to pass movement authorities to the train. Level 3 uses train reported position and integrity to determine if it is safe to issue the movement authority. Level 3 is currently under development. Solutions for reliable train integrity supervision are highly complex and are hardly suitable for transfer to older models of freight rolling stock. The Confirmed Safe Rear End (CSRE) is the point in rear of the train at the furthest extent of the safety margin. If the Safety margin is zero, the CSRE aligns with the Confirmed Rear End. Some kind of end-of-train device is needed or special lines for rolling stock with included integrity checks like commuter multiple units or high speed passenger trains. A ghost train is a vehicle in the Level 3 Area that are not known to the Level 3 Track-side. ERTMS RegionalA variant of Level 3 is ERTMS Regional, which has the option to be used with virtual fixed blocks or with true moving block signalling. It was early defined and implemented in a cost sensitive environment in Sweden. In 2016 with SRS 3.5 it was adopted by core standards and is now officially part of Baseline 3 Level 3. It is possible to use train integrity supervision, or by accepting limited speed and traffic volume to lessen the effect and probability of colliding with detached rail vehicles. ERTMS Regional has lower commissioning and maintenance costs, since trackside train detection devices are not routinely used, and is suitable for lines with low traffic volume. These low-density lines usually have no automatic train protection system today, and thus will benefit from the added safety. GNSSInstead of using fixed balises to detect train location there may be "virtual balises" based on satellite navigation and GNSS augmentation. Several studies about the usage of GNSS in railway signalling solutions have been researched by the UIC (GADEROS/GEORAIL) and ESA (RUNE/INTEGRAIL). Experiences in the LOCOPROL project show that real balises are still required in railway stations, junctions, and other areas where greater positional accuracy is required. The successful usage of satellite navigation in the GLONASS-based Russian ABTC-M block control has triggered the creation of the ITARUS-ATC system that integrates Level 2 RBC elements - the manufacturers Ansaldo STS and VNIIAS aim for certification of the ETCS compatibility of this system. The first real implementation of the virtual balise concept has been done during the ESA project 3InSat on 50 km of track of the Cagliari-Golfo Aranci Marittima railway on Sardinia in which a SIL-4 train localisation at signalling system level has been developed using differential GPS. There is a pilot project "ERSAT EAV" running since 2015 with the objective to verify the suitability of EGNSS as the enabler of cost-efficient and economically sustainable ERTMS signalling solutions for safety railway applications. Ansaldo STS has come to lead the UNISIG working group on GNSS integration into ERTMS within Next Generation Train Control (NGTC) WP7, whose main scope is to specify ETCS virtual balise functionality, taking into account the interoperability requirement. Following the NGTC specifications the future interoperable GNSS positioning systems, supplied by different manufacturers, will reach the defined positioning performance in the locations of the virtual balises.