Trying to use NSXMLParser to parser into an NSMutableArray - overwriting

I've read some of the other answers on here, but I can't seem to find what my problem is. I'm trying to hook up to the TFL XML feed using an NSXMLParser. I've created a parser class that implements the NSXMLParserDelegate.

It parses through the XML fine, but when it comes to adding to the Array, different permuatations of what I have done have either added nothing to the array, continuously overwritten the same object in the array or else added a new object to the array whilst overwriting all existing objects in the array

Every TubeLine has a name property, and from stepping through the code, the name property of all 'TubeLine' objects changes when the `self.currentParsedStringDataz changes.

Appreciate any help!

- (instancetype)initWithData:(NSData *)parseData {

    self = [super init];
    if (self) {
        _tubeLineData = [parseData copy];

        self.parsedTubeLines = [[NSMutableArray alloc] init];
        self.currentParsedStringData = [[NSMutableString alloc] init];
    }
    return self;
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict {

    if ([elementName isEqualToString:kEntryElementName]) {
        TubeLine *tubeLine = [[TubeLine alloc] init];
        self.tubeLine = tubeLine;

    } else if ([elementName isEqualToString:kNameElementName]) {
        _accumulatingParsedCharacterData = YES;
        [self.currentParsedStringData setString:@""];
    }
}


- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {

    if ([elementName isEqualToString:kEntryElementName]) {

        [self.parsedTubeLines addObject:[self.tubeLine mutableCopy]];

    } else if ([elementName isEqualToString:kNameElementName]) {

        self.tubeLine.lineName = self.currentParsedStringData;        
    }
    self.accumulatingParsedCharacterData = NO;
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {

    if (self.accumulatingParsedCharacterData) {

        [self.currentParsedStringData appendString:string];
    }
}